WO2016024629A1 - Near-field polarization microscope - Google Patents

Near-field polarization microscope Download PDF

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Publication number
WO2016024629A1
WO2016024629A1 PCT/JP2015/072930 JP2015072930W WO2016024629A1 WO 2016024629 A1 WO2016024629 A1 WO 2016024629A1 JP 2015072930 W JP2015072930 W JP 2015072930W WO 2016024629 A1 WO2016024629 A1 WO 2016024629A1
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WIPO (PCT)
Prior art keywords
light
sample
field
magnetic
probe
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PCT/JP2015/072930
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French (fr)
Japanese (ja)
Inventor
保坂　純男
逸人 曾根
友 尹
健 三浦
Original Assignee
株式会社ユニソク
国立大学法人群馬大学
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Application filed by 株式会社ユニソク, 国立大学法人群馬大学 filed Critical 株式会社ユニソク
Publication of WO2016024629A1 publication Critical patent/WO2016024629A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01Q—SCANNING-PROBE TECHNIQUES OR APPARATUS; APPLICATIONS OF SCANNING-PROBE TECHNIQUES, e.g. SCANNING PROBE MICROSCOPY [SPM]
    • G01Q60/00—Particular types of SPM [Scanning Probe Microscopy] or microscopes; Essential components thereof
    • G01Q60/18—SNOM [Scanning Near-Field Optical Microscopy] or apparatus therefor, e.g. SNOM probes
    • G01Q60/22—Probes, their manufacture, or their related instrumentation, e.g. holders
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01Q—SCANNING-PROBE TECHNIQUES OR APPARATUS; APPLICATIONS OF SCANNING-PROBE TECHNIQUES, e.g. SCANNING PROBE MICROSCOPY [SPM]
    • G01Q60/00—Particular types of SPM [Scanning Probe Microscopy] or microscopes; Essential components thereof
    • G01Q60/02—Multiple-type SPM, i.e. involving more than one SPM techniques

Definitions

  • the present invention relates to a near-field polarization microscope in which information on a sample is detected using near-field light generated when light enters a probe.
  • a magnetic force microscope has been used to detect a magnetic domain of a sample formed from a magnetic material.
  • the cantilever of the magnetic force microscope has magnetism as described in the background art section of Patent Document 1 below. Since the cantilever has magnetism, a magnetic field generated from the surface of the sample can be measured.
  • the cantilever since the cantilever has magnetism, it is difficult to detect the magnetic domain of the sample while applying a magnetic field from the outside to the sample. This is because a magnetic cantilever is affected by a magnetic field applied from the outside, and an accurate magnetic domain of the sample cannot be detected.
  • the problem to be solved by the present invention is to provide a near-field polarization microscope capable of accurately detecting a magnetic domain of a sample while applying a magnetic field from the outside to the sample. It is also desirable to provide a near-field polarization microscope that can easily measure minute and local magnetic hysteresis of a sample.
  • the present invention has been made to solve the above problems, and the first invention is a near-field polarization microscope capable of detecting a magnetic domain of a sample having at least a surface having magnetism, and is formed of a nonmagnetic material.
  • the probe has a concave shape that tapers toward the tip.
  • the probe is formed of a dielectric and the inner surface is covered with a metal film, and an atom is formed between the probe and the sample.
  • a cantilever arranged so that an interatomic force acts, a magnetic domain detection optical system capable of detecting a magnetic domain of the sample by near-field light by irradiation of the inner surface of the probe with magnetic domain detection laser light, and a wavelength of the magnetic domain detection laser light
  • An observation illumination optical system capable of observing the irradiation state of the magnetic domain detection laser light by an optical image of the return light from the cantilever of illumination light having a wavelength band other than the above, and the magnetic domain detection optical system and the observation illumination optical system.
  • an objective lens provided in common, and a magnetic field applying means that has an upper magnetic pole and a lower magnetic pole that are disposed above and below the cantilever and the sample and that can apply a magnetic field to the sample from the outside. This is a near-field polarized light microscope.
  • a scanning unit that scans the sample in a two-dimensional plane, a coordinate recording unit that moves the sample by a set amount by the scanning unit, and records a z coordinate at each point, and a set value.
  • a magnetic field changing means for changing the external magnetic field; and a storage means for storing information when the external magnetic field is changed at each of the points, and based on the information from the magnetic domain detection optical system, It is a near-field polarization microscope characterized by being able to measure the magnetic hysteresis of a region.
  • the third invention is a near-field polarization microscope characterized in that an upper end portion of the lower magnetic pole is tapered toward the upper side.
  • the fourth invention is a near-field polarization microscope characterized in that the magnetic domain detection optical system includes two quenchable polarizers.
  • the polarizer is configured to quench the other light from the light including the near-field light reflected by the sample and the other light, and to reflect the near-field light reflected by the sample. And the other light can be separated from each other in the traveling direction of the light including the near-field light reflected by the sample and the other light.
  • the other GT analyzer is arranged on the downstream side of the analyzer, and the probe is smaller than the time of detecting the magnetic domain of the sample so that the atomic force between the probe and the sample becomes so small that it can be ignored.
  • One GT analyzer and the other GT analyzer are adjusted so that the light detected by the light detection device provided in the magnetic domain detection optical system is minimized in a state separated from the sample.
  • the other GT analyzer is rotated to rotate the detection device.
  • the near-field polarized light microscope is characterized in that the light intensity detected in (1) is set to be between a minimum value and a maximum value.
  • the magnetic domain detection optical system is capable of separating light including the near-field light reflected by the sample and other light into linearly polarized light components in two directions.
  • the difference between the light intensity of one of the linearly polarized light components and the light intensity of the other of the linearly polarized light components is the sum of the light intensity of one of the linearly polarized light components and the light intensity of the other linearly polarized light component. It is a near-field polarization microscope characterized by dividing by.
  • the observation illumination optical system includes an imaging lens and a camera, and a magnification of an optical microscope including the objective lens, the imaging lens, and the camera is approximately 1000 times. It is a field polarization microscope.
  • the magnetic domain detection optical system is configured to quench the other light from the light including the near-field light reflected by the sample and the other light and reflect the light from the sample.
  • a GT analyzer capable of separating the near-field light and the other light and a detection device capable of detecting the light, and the interatomic space between the probe and the sample.
  • the GT analyzer is configured so that the light detected by the detection device is minimized when the probe is separated from the sample than when the magnetic domain of the sample is detected so that the force is negligibly small.
  • the magnetic domain of the sample is detected in a contact state where the probe is in contact with the sample or in a non-contact state where a gap formed between the probe and the sample is maintained. Is done A near-field polarizing microscope, characterized.
  • the cantilever when the cantilever is formed of a nonmagnetic material, when the magnetic field is applied to the sample by the magnetic field applying means in which the upper magnetic pole and the lower magnetic pole are arranged with the cantilever interposed therebetween, the cantilever is There is no influence of the magnetic field by the applying means. Therefore, the magnetic domain of the sample can be accurately detected while applying a magnetic field to the sample from the outside. Further, by using near-field light, the magnetic domain of the sample can be detected with a resolution exceeding the diffraction limit of light.
  • fine and local magnetic hysteresis of the sample can be obtained together with the AFM image.
  • the upper end portion of the lower magnetic pole is tapered, so that the magnetic field by the magnetic field applying means can be further strengthened.
  • the other light is more reliably quenched from the light including the near-field light and the other light, and the near-field light and Other light is more reliably separated and the magnetic domain information contained in the near-field light can be extracted more reliably.
  • the polarizer is a GT analyzer having a large extinction ratio, so that the near-field light to be measured and the other light can be more reliably separated from each other.
  • the magnetic domain information contained therein can be extracted more reliably.
  • the polarization beam splitter by providing the polarization beam splitter, it is possible to separate light including near-field light and other light into linearly polarized light components in two directions. Then, by dividing the difference between the light intensities of the two linearly polarized light components by the sum of the light intensities of the two linearly polarized light components, the noise can be suppressed and only the magnetic Kerr effect can be measured. Thereby, it is possible to more reliably extract information on the near-field light that is the measurement target from the light including the near-field light and other light. That is, the deflection information of the near field region on the sample surface can be obtained.
  • the observation position of the sample and the irradiation position of the magnetic domain detection laser light on the probe can be monitored by setting the magnification of the optical microscope to a high magnification of about 1000 times. Thereby, the detection accuracy of the magnetic domain of a sample can be improved.
  • the other light is quenched from the light including the near-field light and the other light, and the near-field light and the other light are extinguished. And the magnetic domain information included in the near-field light can be extracted.
  • FIG. 1 and 2 are diagrams showing an embodiment of the near-field polarization microscope of the present invention.
  • FIG. 1 is a schematic configuration diagram showing a part thereof in cross section
  • FIG. 2 is an enlarged part of FIG. It is a schematic diagram and a part is further enlarged and shown.
  • the near-field polarization microscope 1 of the present embodiment includes a cantilever 3 having a probe 2, a magnetic domain detection optical system 4, an observation illumination optical system 5, an objective lens common to the magnetic domain detection optical system 4 and the observation illumination optical system 5. 6 and magnetic field applying means 7.
  • the sample 8 is not limited to this, and it is sufficient that at least the surface has magnetism.
  • the cantilever 3 is made of a non-magnetic and non-conductive material that transmits light, and is made of silicon nitride in this embodiment. As shown in FIG. 2, the cantilever 3 has a one-end support type configuration and includes a plate-like beam portion 9 and a probe 2 provided at the other end portion of the beam portion 9. The cantilever 3 can be bent with one end side (the side opposite to the side where the probe 2 is formed) as a fulcrum. Further, the cantilever 3 is a dielectric, and in this embodiment, for example, SiO 2 , Si 3 N 4 , SiN or the like is used.
  • the probe 2 of the cantilever 3 has a concave shape that tapers toward the tip, and is formed in an inverted conical shape in this embodiment.
  • the shape of the probe 2 is not limited to an inverted conical shape, and may be formed in an inverted pyramid shape, for example.
  • a through hole is not formed at the tip of the probe 2.
  • a metal film 10 is formed on the entire inner surface of the probe 2 so that surface plasmon resonance occurs. In this embodiment, the film 10 is formed by metal vapor deposition using a metal such as gold, silver, or aluminum.
  • the magnetic domain detection optical system 4 detects the magnetic domain of the sample 8.
  • the magnetic domain detection optical system 4 includes a laser light source 12 for the magnetic domain detection laser light 11, a diaphragm 13 for the magnetic domain detection laser light 11 from the laser light source 12, a ⁇ / 2 plate 14, a ⁇ / 4 plate 15, and a dichroic mirror 16. With. As shown in FIG. 1, an aperture 13, a ⁇ / 2 plate 14, a ⁇ / 4 plate 15, and a dichroic mirror 16 are arranged in the order closer to the laser light source 12 along the optical path of the magnetic domain detection laser beam 11.
  • the magnetic domain detection laser light 11 has a red wavelength of 633 nm, for example.
  • the wavelength of the magnetic domain detection laser beam 11 is not limited to this, and may be a wavelength near the plasmon resonance wavelength of the cantilever.
  • the magnetic domain detection optical system 4 includes a detection device 17 that detects the magnetic domain of the sample 8, a narrow band interference filter 18, a lens 19, and a GT (Glan-Thompson) analyzer 20, and ⁇ / 4. It further includes a plate 21 and unnecessary light eliminating means 22 for eliminating unnecessary light to the detection device 17.
  • the narrow band interference filter 18 is a filter that passes only light of a specific wavelength, and unnecessary light such as a surrounding fluorescent lamp is cut off, and only the laser light can pass.
  • the detection device 17 can detect the magnetic domain of the sample 8 by the return light from the sample 8 due to the irradiation of the sample 8 with light.
  • the detection device 17 is capable of detecting light.
  • a photodiode or a photomultiplier tube is used depending on the mode of return light from the sample 8 to be introduced, the target detection signal mode, and the like.
  • the detection device 17 is a photomultiplier tube.
  • the unnecessary light eliminating means 22 includes a pair of confocal lenses 23 that form a confocal point with the tip of the probe 2 and an aperture 24 that is disposed between the confocal lenses 23, so that the vicinity of the tip of the probe 2. It is possible to obtain limited light only in the focal region and exclude other light.
  • the GT analyzer 20 separates the near-field light of the sample 8 and the other light by quenching the other light from the light including the near-field light of the sample 8 and the other light. It is something that can be done.
  • the observation illumination optical system 5 observes the irradiation state of the magnetic domain detection laser beam 11 on the cantilever 3 and the positional relationship between the probe 2 and the sample 8.
  • the observation illumination optical system 5 includes an illumination light source 25, a beam splitter 26, an imaging lens 27, and an observation device 28 that observes an optical image of the return light from the sample 8.
  • the illumination light source 25 is, for example, a white light source that generates white illumination light 29.
  • the beam splitter 26 is used for introducing illumination light 29 from the illumination light source 25 onto the optical axis or paraxial axis of the objective lens 6 described later.
  • the observation device 28 includes a camera 30 and a monitor 31 on which an imaging optical image is projected.
  • the objective lens 6 common to the observation illumination optical system 5 and the magnetic domain detection optical system 4 is a lens disposed closest to the sample 8.
  • the magnetic domain detection laser beam 11 is a red laser beam.
  • the illumination light source 25 has a wavelength band extending over a wavelength other than the wavelength of the magnetic domain detection laser beam 11, and a wavelength band extending over a wavelength other than the red wavelength in this embodiment.
  • a white light source is used.
  • the magnetic field applying means 7 applies a magnetic field to the sample 8 from the outside.
  • the magnetic field applying means 7 includes a base body 32 and a coil 33 provided on the base body 32.
  • the base 32 includes a main body 34 and a lid 35 provided at the upper end of the main body 34.
  • the main body 34 is a cylinder and is a cylinder arranged so as to form a cylindrical gap 37 between the iron core 36 and an iron core 36 formed from a truncated cone-shaped ferromagnetic material whose upper end portion tapers upward.
  • a disk-shaped connecting portion 39 to which the lower end portion of the iron core 36 and the lower end portion of the cylindrical portion 38 are connected.
  • each of the iron core 36 and the cylindrical portion 38 is fixed to the connecting portion 39 with screws.
  • the lid 35 is formed in a disk shape, and a notch 40 is formed in part.
  • a mounting portion 41 is formed extending downward in a cylindrical shape.
  • a circular introduction hole 42 is formed in the central portion of the lid 35 so as to penetrate the plate surface, and the introduction hole 42 and the cutout portion 40 communicate with each other.
  • the coil 33 is disposed in the cylindrical gap 37.
  • the mounting portion 41 of the lid body 35 is fixed to the upper surface of the cylindrical portion 38 of the main body 34 with screws.
  • the lid 35 is the upper magnetic pole 43, while the iron core 36 of the base body 32 is the lower magnetic pole 44.
  • a space is formed between the upper magnetic pole 43 and the lower magnetic pole 44 by the mounting portion 41 of the lid 35.
  • a through hole 45 is formed in the mounting portion 41 of the lid 35 along the circumferential direction at a position facing the notch 40 of the lid 35 in the radial direction.
  • the diameter and thickness of the introduction hole 42 are appropriately set according to the working distance and focus of the objective lens 6 and other numerical aperture (NA). Further, the shape of the introduction hole 42 is not limited to a circular shape, and can be appropriately changed according to the working distance, the focal point, and the numerical aperture of the objective lens 6. Thereby, even if it is the structure of the magnetic field application means 7 of a present Example, a large numerical aperture and a short focus are realizable.
  • the near-field polarizing microscope 1 includes a dichroic mirror 46, a probe stage 48 provided with a probe support piece 47, a sample stage 50 provided with a sample support piece 49, and a sample scanner. 51 is further provided.
  • the sample stage 50 is provided on the sample scanner 51, but conversely, the sample scanner 51 may be provided on the sample stage 50.
  • the dichroic mirror 46 can reflect the wavelength light of the magnetic domain detection laser beam 11, which is red light of 633 nm in this embodiment. At this time, part of the red light passes through the dichroic mirror 46. In this way, it is possible to visually recognize the beam spot with the glare reduced by the transmitted red light while the light intensity is attenuated, and the position of the red beam can be monitored by the camera. Further, the dichroic mirror 46 has a wavelength selectivity that allows light having a wavelength other than the wavelength of the magnetic domain detection laser light 11 to pass therethrough and directs the illumination light 29 together with the magnetic domain detection laser light 11 toward the objective lens 6.
  • the sample stage 50 can be moved by the sample scanner 51 in the z-axis direction along the optical axis direction of the near-field polarization microscope 1 and in the x-axis and y-axis directions orthogonal to each other on a plane orthogonal to the z-axis direction.
  • the cantilever 3 is arranged so that the tip of the probe 2 is close to the surface of the sample 8 so that an atomic force acts between the probe 2 and the sample 8.
  • the cantilever 3 is provided in the crystal resonator 52.
  • the crystal resonator 52 is formed by cutting one of the two vibrating pieces 53, and the cantilever 3 is bonded to the remaining vibrating piece 53.
  • the crystal unit 52 is provided on the probe holder 56 via a ceramic base 54, and the probe holder 56 is provided on the probe support piece 47.
  • the probe holder 56 and the probe support piece 47 are made of a nonmagnetic and nonconductive material, and are made of ceramic such as alumina in this embodiment.
  • the probe support piece 47 is formed in an elongated plate shape, and a probe holder 56 is provided at the tip. The tip of the probe support piece 47 is inserted into the base 32 through the notch 40 of the lid 35. At this time, the cantilever 3 is arranged between the upper magnetic pole 43 and the lower magnetic pole 44, and the probe 2 is arranged corresponding to the introduction hole 42 of the lid 35.
  • the sample 8 is provided on the sample support piece 49 via the sample holder 57.
  • the sample holder 57 and the sample support piece 49 are made of a nonmagnetic and nonconductive material, and are made of ceramic such as alumina in this embodiment.
  • the sample support piece 49 is formed in an elongated plate shape, and a sample holder 57 is provided at the tip.
  • the sample support piece 49 is inserted into the base body 32 through a through hole 45 formed in the lid body 35. At this time, the sample 8 is disposed below the cantilever 3 between the upper magnetic pole 43 and the lower magnetic pole 44 and corresponding to the introduction hole 42 of the lid 35.
  • the near-field light By focusing the far field light of the magnetic domain detection laser light 11 irradiated from the laser light source 12 on the tip of the probe 2, plasmon resonance is excited at the interface between the probe 2 and the film 10, and this is a through hole at the tip. Is propagated to the tip side of the probe 2 where no is formed, near-field light (near-field light) is generated from the tip, and the near-field light is irradiated to the sample 8.
  • the spot diameter due to the near-field light is not restricted by the diffraction limit, and does not depend on the numerical aperture of the objective lens 6 and the wavelength of the magnetic domain detection laser light 11, so that it can be a very small irradiation spot diameter.
  • a magnetic field is applied to the sample 8 from the outside by the magnetic field applying means 7. Specifically, by applying a current to the coil 33, the lid 35 and the iron core 36 become magnetic poles 43 and 44, respectively, and a magnetic field can be generated. Thereby, in a present Example, a strong magnetic field, for example, a 1 Tesla magnetic field, can be generated. In this way, the magnetic domain of the sample 8 can be detected while applying a magnetic field from the outside.
  • a strong magnetic field for example, a 1 Tesla magnetic field
  • the illumination light 29 is reflected by the beam splitter 26, passes through the dichroic mirror 46, is collected by the objective lens 6, and is passed through the introduction hole 42 of the lid 35 and the cantilever 3 and the sample. 8 is irradiated.
  • the return light of the illumination light 29 applied to the cantilever 3 and the sample 8 passes through the lens 27 and is observed by the observation device 28.
  • the reference position of the sample 8 is adjusted by the sample scanner 51.
  • the sample scanner 51 can move the sample stage 50 in the xy direction (horizontal direction) and the z direction (vertical direction). Note that the setting position of the cantilever 3 is adjusted as necessary.
  • the sample stage 50 is moved in the x and y directions by the sample scanner 51, and the spot of the near-field light from the tip of the probe 2 by the magnetic domain detection laser beam 11 is scanned on the surface of the sample 8.
  • the sample 8 is moved while the cantilever 3 is fixed.
  • the magnetic domain detection laser beam 11 passes through the ⁇ / 2 plate 14 through the diaphragm 13 and then passes through the ⁇ / 4 plate 15.
  • the linearly polarized light incident by the ⁇ / 2 plate 14 is rotated, and is converted into circularly polarized light or elliptically polarized light by the ⁇ / 4 plate 15.
  • the circularly polarized far-field light passes through the dichroic mirror 16, is reflected by the mirror 58 and the mirror 59, is reflected by the dichroic mirror 46, is collected by the objective lens 6, and is introduced into the introduction hole 42 of the lid 35.
  • the near-field light is obtained from the tip, and the sample 8 is irradiated with the near-field light.
  • the near-field light irradiated on the sample 8 passes through the objective lens 6 as reflected light on the surface of the sample 8, is reflected by the dichroic mirror 46, is reflected by the mirror 59 and the mirror 58, and is further reflected by the dichroic mirror 16.
  • the detection device 17 provided in the magnetic domain detection optical system 4 detects the polarization rotation due to the presence of the magnetic domain on the surface of the sample 8 as a change in light intensity, and detects the magnetic domain of the sample 8.
  • the polarization plane is rotated according to the magnetization direction of the sample 8.
  • Such return light travels from the objective lens 6 to the dichroic mirror 16 as described above, and further travels to the ⁇ / 4 plate 21 via the unnecessary light exclusion means 22.
  • the return light of unnecessary far-field light reflected by the inner surface of the probe 2 also travels from the objective lens 6 to the dichroic mirror 16 in the same manner as the return light of near-field light, and further passes through the unnecessary light exclusion means 22. Then, the process proceeds to the ⁇ / 4 plate 21.
  • the return light from the sample 8 and the return light of unnecessary far-field light reflected from the inner surface of the probe 2 have different optical path lengths to the ⁇ / 4 plate 21.
  • both return lights converted into linearly polarized light by the ⁇ / 4 plate 21 are introduced into the GT analyzer 20 with the angles of the polarization planes being different.
  • the GT analyzer 20 is adjusted before the magnetic domain of the sample 8 is detected. Specifically, the GT analyzer 20 is in a state in which the probe 2 is separated from the sample 8 than when the magnetic domain of the sample 8 is detected (the probe 2 is smaller than the surface of the sample 8 so that the atomic force can be ignored). In the state of being separated to the position), the light detected by the detection device 17 is adjusted to be minimum.
  • the probe 2 is separated from the sample 8 by 20 nm or more and the atomic force between the probe 2 and the sample 8 is small, and the light detected by the detection device 17 is almost zero or the minimum value.
  • the GT analyzer is rotated and adjusted so that After this adjustment, the atomic force is controlled to be constant by setting the probe 2 in contact with the sample 8 or in the non-contact state in which the gap formed between the probe 2 and the sample 8 is maintained.
  • the magnetic domain detection of the sample 8 is performed.
  • by adjusting the polarization angle of the GT analyzer 20 as described above it is possible to extract only the reflected near-field light.
  • the polarization angle of the GT analyzer 20 may be adjusted so that the light intensity detected by the detection device 17 is between the minimum value and the maximum value. This adjustment of the polarization angle is performed, for example, by rotating the GT analyzer 20 by about 45 degrees from a state in which the light detected by the detection device 17 is adjusted to be substantially zero. As described above, the return light of unnecessary far-field light reflected by the inner surface of the probe 2 is eliminated, and only the light thus guided passes through the lens 19 and the narrowband interference filter 18. An output introduced into the detection device 17 and converted into an electric signal can be taken out.
  • diffracted light that is not in a confocal relationship by the pair of confocal lenses 23, 23 can be cut off by being cut off by the aperture 24 arranged at the confocal position.
  • the diameter of the pinhole of the aperture 24 is the same as the focal length of the confocal lens 23 and the objective lens 6 so that only the signal can be detected. It is set by determining the ratio to the focal length and the range to be observed near the tip of the probe 2.
  • the cantilever 3 is controlled so that the distance between the probe 2 and the sample 8 is constant.
  • the crystal resonator 52 provided with the cantilever 3 is provided with an excitation electrode and a detection electrode (not shown).
  • the vibrating piece 53 of the crystal resonator 52 is flexibly vibrated, thereby causing the probe 2 of the cantilever 3 to vibrate in a direction substantially perpendicular to the surface of the sample 8. be able to.
  • the sample scanner 51 includes fine movement means that can adjust the distance between the probe 2 and the sample 8, and scanning means that relatively scans the probe 2 and the sample 8 in a two-dimensional plane. .
  • the sample scanner 51 and the sample stage 50 are connected, so that the sample stage 50 and eventually the sample 8 can be moved by the sample scanner 51 in the xy direction (horizontal direction) and the z direction (vertical direction). .
  • the tip of the probe 2 and the surface of the sample 8 are brought close to each other in a state in which an alternating voltage is applied to the crystal unit 52 and the resonator element 53 is resonated.
  • an atomic force acts between the tip of the probe 2 and the surface of the sample 8, and the vibration state such as the frequency and amplitude of the vibrating piece 53 changes, and the piezoelectric current generated by the vibration of the quartz crystal resonator 52. Is changed.
  • the cantilever 3 is attached to the tip of the crystal resonator 52, if the resonance frequency of the cantilever 3 itself is smaller than that of the crystal resonator 52, it becomes difficult to detect the atomic force, so the resonance frequency is higher than that of the crystal resonator 52. It is attached so as to be short. In this way, when the cantilever 3 is attached to the crystal resonator 52, the resonance frequency of the cantilever 3 is made smaller than that of the crystal resonator 52.
  • a PLL (Phase Locked Loop) circuit 61 is connected to the detection electrode of the crystal resonator 52 via a preamplifier 60.
  • the preamplifier 60 the piezoelectric current generated by the vibration of the crystal resonator 52 is detected and amplified and changed into an electric signal, which is output to the PLL circuit 61.
  • the amount of change in the resonance frequency of the resonator element 53 is detected, an electric signal representing the amount of change is generated, and the generated electric signal is output to the control unit 62.
  • the control unit 62 outputs a control signal to the sample scanner 51 so that the above-described frequency change amount is kept constant. Then, the sample 8 is moved relative to the probe 2 in a two-dimensional plane while adjusting the distance between the probe 2 and the sample 8 to be constant by the sample scanner 51.
  • the near-field polarizing microscope 1 of the present embodiment it is preferable that the magnetic hysteresis in the minute region of the sample 8 can be measured together with the AFM image.
  • the near-field polarizing microscope 1 of this embodiment moves the sample 8 by a set amount by the scanning unit of the sample scanner 51 and records the z coordinate at each point, and an external magnetic field between the set values. And a storage means for storing information when the external magnetic field is changed at each of the points.
  • a terminal device constituted by a personal computer and the sample scanner 51 are connected, and the set amount may be set in the terminal device.
  • the coordinate recording means is means for recording the z coordinate at each point of the sample 8.
  • the coordinate recording means is connected to the sample scanner 51 and can record the information of the z coordinate sent from the sample scanner 51.
  • the z coordinate is the height information of the undulation of the sample 8.
  • the z coordinate is recorded in the coordinate recording means in association with the xy coordinate (location on the sample surface) of the sample 8.
  • the magnetic field changing means is provided in the magnetic field applying means 7 and connected to the terminal device. In this terminal device, the value of the magnetic field to be changed is set. In this embodiment, for example, it is set so as to continuously vary from +1 Tesla to -1 Tesla and from -1 Tesla to +1 Tesla.
  • the storage means is connected to the detection device 17 and can store information when the magnetic field is changed by the external magnetic field changing means at each point.
  • an AFM image can be obtained by two-dimensionally displaying the acquired z coordinate information.
  • two three-dimensional magnetic hysteresis data can be obtained in which the magnetic field axis (or magnetic field axis) is taken as the z axis and the surface location of the sample is shown as the xy axis.
  • the magnetic hysteresis and the AFM image for each point can be acquired in synchronization.
  • the two are a case where the magnetic field is changed from -1 Tesla to +1 Tesla and a case where the magnetic field is changed from +1 Tesla to -1 Tesla, which is one set of reciprocation. .
  • a magnetic image two-dimensional
  • the magnetic hysteresis curve at that location may be extracted.
  • the cantilever 3 disposed between the upper magnetic pole 43 and the lower magnetic pole 44 is formed of a nonmagnetic material. It is not affected by the applied magnetic field. Therefore, the magnetic domain of the sample 8 can be accurately detected while applying a magnetic field from the outside.
  • the cantilever 3, the sample support piece 49, the sample holder 57, the probe holder 56, and the probe support piece 47 are formed of a nonconductive material, so that the vortex The influence of current can be suppressed.
  • the cantilever 3, the sample support piece 49, the sample holder 57, the probe holder 56, and the probe support piece 47 are formed of the nonmagnetic material and the nonconductive material, so that not only the magnetic field attractive force is obtained. , The influence of the magnetic field fluctuation can be eliminated.
  • the sample support piece 49 and the probe support piece 47 are inserted from the outer peripheral surface of the base 32 between the upper magnetic pole 43 and the lower magnetic pole 44.
  • the distance between the upper magnetic pole 43 and the lower magnetic pole 44 can be reduced to make the magnetic field stronger.
  • the magnetic domain of the sample 8 can be detected using the near-field light while applying a magnetic field, so that the change in the magnetization of the magnetic dot in the minute region can be observed. Can do.
  • the upper end portion of the lower magnetic pole 44 is formed to be tapered, so that the distance between the upper magnetic pole 43 and the lower magnetic pole 44 is reduced and the magnetic field is made stronger. Can do.
  • the near-field polarizing microscope of the present invention is not limited to the configuration of the above-described embodiment, and can be changed as appropriate.
  • the magnetic field applying unit 7 is not limited to the configuration of the above embodiment.
  • 3 and 4 are views showing a modification of the near-field polarization microscope of FIG. 1, FIG. 3 is a schematic side view of the magnetic field applying means, and FIG. 4 is a schematic plan view of the magnetic field applying means. And a sample are arranged.
  • the magnetic field applying means 7 of this modification is provided on the iron core 72, an upper return yoke 70 and a lower return yoke 71 that are spaced apart from each other, an iron core 72 that connects the upper return yoke 70 and the lower return yoke 71, and And a column body 74 provided on the lower return yoke 71.
  • One end of the upper return yoke 70 and the lower return yoke 71 are connected by a cylindrical iron core 72, and a coil 73 is provided on the iron core 72.
  • the column 74 is formed in a columnar shape and is erected on the other end of the lower return yoke 71.
  • the other end of the upper return yoke 70 and the upper end of the column 74 are disposed so as to correspond to each other with a gap left therebetween.
  • the upper end of the column 74 is formed in a truncated cone shape that tapers as it goes upward.
  • the upper return yoke 70 is the upper magnetic pole 43
  • the column body 74 is the lower magnetic pole 44.
  • the iron core 72 is not limited to a columnar shape, and may be formed in a rectangular column shape, for example, in terms of space efficiency.
  • the cantilever 3 and the sample 8 are disposed in a gap between the upper return yoke 70 that becomes the upper magnetic pole 43 and the column body 74 that becomes the lower magnetic pole 44.
  • the upper return yoke 70 and the column 74 become the upper magnetic pole 43 and the lower magnetic pole 44, respectively, and a magnetic field can be generated and the magnetic field can be applied to the sample 8. it can.
  • the elongated plate-like probe support piece 47 and the sample support piece 49 are not required, but the other cantilevers 3, the holders 56 and 57, etc. are made of a nonmagnetic material, so that the influence of the magnetic field is reduced. I do not receive it.
  • the influence of eddy currents can be suppressed by forming them from a non-conductive material. That is, by being formed from a nonmagnetic material and a nonconductive material, it is possible to eliminate not only the attractive force of the magnetic field but also the influence of the magnetic field fluctuation.
  • the whole near-field polarizing microscope 1 can be made compact. Furthermore, the near-field polarizing microscope 1 using the magnetic field applying means 7 of this modification can easily apply the configuration of an existing atomic force microscope.
  • FIG. 5 is a schematic configuration diagram showing another modified example of the near-field polarization microscope of FIG. 1, and a part thereof is omitted.
  • the near-field polarizing microscope 1 of this modification example has basically the same configuration as that of the above embodiment. Therefore, in the following description, differences between the two will be mainly described, and corresponding portions will be described with the same reference numerals.
  • the cantilever 3 is directly provided on the excitation piezo 55.
  • the excitation piezo 55 is provided on the probe holder 56 described above, and the probe holder 56 is provided on the probe support piece 47 described above.
  • the excitation piezo 55 is excited at the resonance frequency of the cantilever 3 from an output device (not shown). Accordingly, the vibration of the excitation piezo 55 is transmitted to the cantilever 3 and the cantilever 3 is vibrated.
  • the near-field polarization microscope 1 of this modification further includes a displacement detection optical system 63 that detects the displacement of the cantilever 3 and a dichroic mirror 64.
  • the displacement detection optical system 63 includes a displacement laser light source 66 for the displacement detection laser light 65, a displacement detection device 67 for detecting the displacement of the cantilever 3 by the light, and a lens 68.
  • the film 10 is continuously formed on the surface of the beam portion 9 from the inner surface of the probe 2 except for one end portion of the beam portion 9.
  • the film 10 is not limited to be formed by leaving one end portion of the beam portion 9, and may be formed on the entire surface of the beam portion 9.
  • the displacement detector 67 is a four-division photodiode in this modification, and can detect the displacement of the cantilever 3 by the return light of the displacement detection laser beam 65 from the cantilever 3.
  • the displacement detection laser beam 65 has a green wavelength of 532 nm, for example.
  • the objective lens 6 is common to the displacement detection optical system 63, the observation illumination optical system 5, and the magnetic domain detection optical system 4. Thereby, simplification of a structure, size reduction of an occupation space, and the improvement of an assembly precision can be aimed at.
  • the dichroic mirror 64 can reflect the wavelength light of the displacement detection laser beam 65, which is green light of 532 nm in this embodiment. At this time, part of the green light passes through the dichroic mirror 64.
  • the dichroic mirror 64 has wavelength selectivity that allows light having a wavelength other than the wavelength of the displacement detection laser light 65 to pass therethrough and directs the illumination light 29 together with the displacement detection laser light 65 toward the objective lens 6.
  • the magnetic domain of the sample 8 is detected in the same manner as the near-field polarizing microscope 1 of the above embodiment.
  • the displacement detection laser light 65 from the displacement laser light source 66 is reflected by the dichroic mirror 64, passes through the dichroic mirror 46, passes through the objective lens 6, and is reflected by the film 10 of the cantilever 3.
  • This return light is introduced into the displacement detection device 67 via the lens 68.
  • the return light changes in the incident angle to the displacement detection device 67 (that is, change in spot position) or the position according to the bending of the cantilever 3, that is, the displacement. A change in the amount of incident light occurs. Therefore, by calculating the output from these, it is possible to detect the deflection of the cantilever 3 and thus the atomic force.
  • a signal that detects the atomic force is input to the control device 69, and a control signal is output from the control device 69 to the sample scanner 51. Then, the sample scanner 51 adjusts the sample stage 50 in the z-axis direction.
  • the distance between the probe 2 and the sample 8 can always be kept constant. In other words, the near-field light is always applied to the surface of the sample 8 under a certain condition.
  • the ⁇ / 4 plate 15 is provided in the magnetic domain detection optical system 4, but this may not be used.
  • the linearly polarized light incident on the magnetic domain detection laser beam 11 by the ⁇ / 2 plate 14 is rotated and proceeds to the dichroic mirror 16.
  • the ⁇ / 4 plate 15 and the ⁇ / 4 plate 21 may not be used.
  • the ⁇ / 2 plate 14 need not be provided because it merely rotates linearly polarized light as described above.
  • the probe support piece 47 and the sample support piece 49 are arranged so as to face each other in the radial direction of the base 32.
  • the present invention is not limited to this, and the probe support piece 47 and You may arrange
  • the detection apparatus 17 was used as the photomultiplier tube, it is good also as a spectrometer. In this case, the narrowband interference filter 18 is not used, and the dichroic mirror 16 and the dichroic mirror 46 are beam splitters that are half mirrors.
  • a beam splitter is disposed between the unnecessary light eliminating means 22 and the ⁇ / 4 plate 21 or between the GT analyzer 20 and the lens 19, and the return light is converted into light directed to the photomultiplier tube and the beam splitter.
  • the light may be branched to the light reflected by.
  • the light reflected by the beam splitter is introduced into the spectrometer, and the detection signal from the photomultiplier tube and the detection signal from the spectrometer can be acquired simultaneously.
  • the frequency of the resonator element 53 of the crystal resonator 52 is detected by the PLL circuit 61. Based on this, the distance between the probe 2 and the sample 8 is kept constant.
  • the above-described displacement detection optical system 63 may be used.
  • the vibration of the cantilever 3 due to the vibration of the excitation piezo 55 is detected by the displacement detection optical system 63.
  • the present invention is not limited to this.
  • the frequency of the excitation piezo 55 is the PLL circuit 61. It is good also as a structure detected by.
  • the PLL circuit 61 is configured to contact the surface of the sample 8 while touching the surface of the sample 8 with the cantilever 3 while detecting the irregularities on the surface of the sample 8 by the movement of the cantilever 3, or by forcibly exciting the cantilever 3 at the resonance frequency. It also supports the tapping method.
  • FIG. 6 is a schematic configuration diagram showing another modified example of the near-field polarization microscope of FIG. 1, and a part thereof is omitted.
  • the near-field polarizing microscope 1 of this modification example has basically the same configuration as that of the above embodiment. Therefore, in the following description, differences between the two will be mainly described, and corresponding portions will be described with the same reference numerals.
  • both polarizers are GT analyzers.
  • the first GT analyzer disposed on the downstream side of the unnecessary light eliminating means 22 described above.
  • 70 and a second GT analyzer 71 disposed downstream of the first GT analyzer 70 in the traveling direction and upstream of the lens 19 in the traveling direction.
  • the first GT analyzer 70 and the second GT analyzer 71 are the same as the GT analyzer 20 described above.
  • the first GT analyzer 70 and the second GT analyzer 71 extinguish the other light from the light including the near-field light reflected by the sample 8 and the other light, so that the sample It is possible to separate the near-field light reflected by and the other light and analyze the deflection state of only the near-field light.
  • the ⁇ / 4 plates 15 and 21 of the above embodiment are not provided.
  • the present invention is not limited to this, and the ⁇ / 4 plates 15 and 21 may be provided. Since other configurations are the same as those in the above-described embodiment, description thereof is omitted.
  • reflected light including the return light from the sample 8 and the return light of unnecessary far-field light reflected by the inner surface of the probe 2 is introduced into the first GT analyzer 70. Is done. Then, the first GT analyzer 70 can extract the reflected near-field light from the sample 8 by removing the return light of the far-field light reflected by the probe 2 from the reflected light. In the first GT analyzer 70, the return light of the far field light reflected by the probe 2 cannot be completely removed from the reflected light, and the extracted light is reflected by the probe 2. The far field light returned light is included.
  • the reflected light that has passed through the first GT analyzer 70 is introduced into the second GT analyzer 71.
  • the second GT analyzer 71 By adjusting the polarization angle of the second GT analyzer 71, the return of far-field light that cannot be removed by the first GT analyzer 70 from the reflected light that has passed through the first GT analyzer 70.
  • the return light from the sample 8 can be extracted by removing the light.
  • the near-field light reflected by the sample 8 and the other light can be more reliably obtained.
  • the near-field light that is the measurement target can be extracted more reliably. That is, the first GT analyzer 70 can quench the diffracted light and separate it from the near-field light, and the second GT analyzer 71 can analyze the deflection of the near-field light.
  • the first GT analyzer 70 and the second GT analyzer 71 are adjusted before the magnetic domain of the sample 8 is detected. Specifically, in the first GT analyzer 70 and the second GT analyzer 71, the probe 2 is more distant from the sample 8 than when the magnetic domain of the sample 8 is detected (the probe 2 is separated from the surface of the sample 8). In a state where the atomic force is separated to a level where it can be ignored, the light detected by the detection device 17 is adjusted to be minimum. In this modification, the light detected by the detection device 17 is almost zero or the minimum value when the probe 2 is separated from the sample 8 by 20 nm or more and the atomic force between the probe 2 and the sample 8 is small. Thus, the first GT analyzer 70 and the second GT analyzer 71 are rotated and adjusted.
  • the atomic force is controlled to be constant by setting the probe 2 in contact with the sample 8 or in the non-contact state in which the gap formed between the probe 2 and the sample 8 is maintained.
  • the light intensity detected by the detection device 17 by rotating the second GT analyzer 71 is set to be between the minimum value and the maximum value. That is, the second GT analyzer is rotated and adjusted so that the light intensity detected by the detection device 17 is between the minimum value and the maximum value. In this modification, the light detected by the detection device 17 is rotated by rotating the second GT analyzer 71 about 45 degrees from the state where the light detected by the detection device 17 is adjusted to be substantially zero.
  • the intensity is set to be between the minimum value and the maximum value.
  • the polarization angle of the second GT analyzer 71 is adjusted. Then, the magnetic domain detection of the sample 8 is performed with the polarization angle of the second GT analyzer 71 adjusted.
  • the return light of unnecessary far-field light reflected on the inner surface of the probe 2 is eliminated, and only the light guided in this way is directly or the lens 19 and the narrowband interference filter 18.
  • the output converted into an electrical signal can be taken out to the detection device 17 via. That is, the magnetic domain of the sample 8 from which noise has been removed can be detected.
  • FIG. 7 is a schematic configuration diagram showing still another modified example of the near-field polarization microscope of FIG. 1, and a part thereof is omitted.
  • the near-field polarizing microscope 1 of this modification example has basically the same configuration as that of the above embodiment. Therefore, in the following description, differences between the two will be mainly described, and corresponding portions will be described with the same reference numerals.
  • the magnetic domain detection optical system 4 includes a laser light source 12, a diaphragm 13, a ⁇ / 2 plate 14, a dichroic mirror 16, an unnecessary light exclusion unit 22, a narrowband interference filter 18, a polarization beam splitter. 72, two detection devices 73 and 74, a differential amplifier 75, an addition amplifier 76, a division amplifier 77, and an image detection unit 78. Since other configurations are the same as those in the above-described embodiment, description thereof is omitted.
  • the unnecessary light eliminating means 22, the narrow band interference filter 18, and the polarization beam splitter 72 are arranged in order from the upstream side.
  • the polarization beam splitter 72 separates the reflected light including the return light from the sample 8 and the return light of unnecessary far-field light reflected by the inner surface of the probe 2 into linearly polarized components in two directions.
  • the detection devices 73 and 74 are configured by, for example, a photodiode, a photomultiplier tube (photomultiplier), a spectroscope, or the like according to the mode of return light from the sample 8 to be introduced and the target detection signal mode. Is done.
  • the detecting device 73 is one in which one of the linearly polarized components separated by the polarizing beam splitter 72 is introduced, and the detecting device 74 is separated into two by the polarizing beam splitter 72. Of the linearly polarized light components, the other linearly polarized light component is introduced.
  • the differential amplifier 75 and the addition amplifier 76 are connected to the detection device 73 and the detection device 74.
  • the division amplifier 77 is connected to the differential amplifier 75 and the addition amplifier 76.
  • the image detection unit 78 is connected to the division amplifier 77. In this modification, the polarization plane incident on the polarization beam splitter 72 is adjusted to be about 45 degrees.
  • the light including the near-field light reflected by the sample 8 by the polarization beam splitter 72 and the other light is separated into linearly polarized light components in two directions.
  • the polarization component is introduced into the detection device 73 and the other linear polarization component is introduced into the detection device 74, and the output converted into an electric signal by both the detection devices 73 and 74 is sent to the differential amplifier 75 and the addition amplifier 76.
  • the difference between the output from the detection device 73 and the output from the detection device 74 is obtained by the differential amplifier 75.
  • the summing amplifier 76 obtains the sum of the output from the detection device 73 and the output from the detection device 74.
  • An output corresponding to the difference is introduced from the differential amplifier 75 to the division amplifier 77, and an output corresponding to the sum is introduced from the addition amplifier 76 to the division amplifier 77.
  • the division amplifier 77 causes the difference to be the sum. Cracked. That is, the difference / the sum is obtained by the division amplifier 77. Then, an output corresponding to the difference / the sum is introduced into the image detection unit 78, and an image with a deflection rotation angle is formed by the image detection unit 78.
  • the reflected light is separated into two directions of linearly polarized light components and detected respectively, and the difference between the light intensities of the two linearly polarized light components is divided by the sum of the light intensities of the two linearly polarized light components. Therefore, the influence of a change in light intensity such as a decrease in incident light source can be suppressed. Thereby, only the deflection change is extracted and corrected, and only the magnetic Kerr effect can be measured. That is, according to the present modification, background noise can be subtracted, and information on near-field light that is a measurement target can be more reliably extracted.
  • the GT analyzer 20 may be disposed upstream of the narrowband interference filter 18, and the first GT analyzer 70 and the second GT analyzer 71 may be disposed. You may arrange. When the GT analyzer 20 is disposed, ⁇ / 4 plates 15 and 21 may be provided. Moreover, in this modification, one linearly polarized light component and the other linearly polarized light component may be recorded separately, and an image may be obtained later by calculation based on the recording.
  • an optical microscope including the objective lens 6, the imaging lens 27, and the camera 30 may be used.
  • the magnification of the optical microscope is preferably a high magnification, for example, about 1000 times.
  • the observation position of the sample 8 and the irradiation position of the magnetic domain detection laser light from the laser light source 12 can be monitored, and thereby the magnetic domain of the sample 8 to be measured can be monitored. Detection accuracy can be improved.
  • membranes 10 may be platinum and copper other than gold

Abstract

[Problem] To provide a near-field polarization microscope with which it is possible to accurately detect a magnetic domain in a sample while applying a magnetic field to the sample from the outside. [Solution] This near-field polarization microscope 1 is provided with: a cantilever 3 having a probe 2; a magnetic domain detection optical system 4 for detecting a magnetic domain in a sample 8 using near-field light produced by irradiating the probe 2 with a magnetic domain detection laser beam 11; an observation illumination optical system 5 for observing the state of irradiation by the magnetic domain detection laser beam 11; an objective lens 6 shared by the magnetic domain detection optical system 4 and the observation illumination optical system 5; and a magnetic field application means 7 for applying a magnetic field to the sample 8 from the outside. The cantilever 3, which is formed from a non-magnetic and electrically non-conductive material, and the sample 8, which is formed from a magnetic material, are arranged between an upper magnetic pole 43 and a lower magnetic pole 44 provided to the magnetic field application means 7.

Description

近接場偏光顕微鏡Near-field polarization microscope
　本発明は、探針に光が入射されることで発生する近接場光を用いて試料の情報が検出される近接場偏光顕微鏡に関するものである。 The present invention relates to a near-field polarization microscope in which information on a sample is detected using near-field light generated when light enters a probe.
　従来から、磁性体から形成される試料の磁区を検出するために、磁気力顕微鏡（ＭＦＭ）が用いられている。磁気力顕微鏡のカンチレバーは、下記特許文献１の背景技術の欄に記載のとおり、磁性を有している。カンチレバーが磁性を有していることで、試料の表面から発生する磁界を測定することができる。 Conventionally, a magnetic force microscope (MFM) has been used to detect a magnetic domain of a sample formed from a magnetic material. The cantilever of the magnetic force microscope has magnetism as described in the background art section of Patent Document 1 below. Since the cantilever has magnetism, a magnetic field generated from the surface of the sample can be measured.
特開２０１２－２３３８４５号公報JP2012-233845A
　しかしながら、磁気力顕微鏡では、カンチレバーが磁性を有しているため、試料に外部から磁界を印加しつつ、試料の磁区を検出することが困難である。これは、磁性を有するカンチレバーが、外部から印加される磁界の影響を受けてしまい、試料の正確な磁区を検出することができないからである。 However, in the magnetic force microscope, since the cantilever has magnetism, it is difficult to detect the magnetic domain of the sample while applying a magnetic field from the outside to the sample. This is because a magnetic cantilever is affected by a magnetic field applied from the outside, and an accurate magnetic domain of the sample cannot be detected.
　本発明が解決しようとする課題は、試料に外部から磁界を印加しつつ、試料の磁区を正確に検出することができる近接場偏光顕微鏡を提供することにある。また、好ましくは、試料の微小で局所的な磁気ヒステリシスを容易に測定できる近接場偏光顕微鏡を提供することにある。 The problem to be solved by the present invention is to provide a near-field polarization microscope capable of accurately detecting a magnetic domain of a sample while applying a magnetic field from the outside to the sample. It is also desirable to provide a near-field polarization microscope that can easily measure minute and local magnetic hysteresis of a sample.
　本発明は、前記課題を解決するためになされたもので、第一発明は、少なくとも表面が磁性を有する試料の磁区を検出することができる近接場偏光顕微鏡であって、非磁性材料から形成され、先端へ行くに従って先細りとなる凹形状の探針を有し、この探針は、誘電体で形成されると共に内面が金属製の膜で覆われ、前記探針と前記試料との間に原子間力が作用するよう配置されるカンチレバーと、磁区検出レーザ光の前記探針内面への照射による近接場光により、前記試料の磁区を検出できる磁区検出光学系と、前記磁区検出レーザ光の波長以外の波長帯を有する照明光の前記カンチレバーからの戻り光の光学像により、前記磁区検出レーザ光の照射状態が観察できる観察照明光学系と、前記磁区検出光学系および前記観察照明光学系に対して共通に設けられる対物レンズと、前記カンチレバーおよび前記試料を挟んで上下に配置される上部磁極および下部磁極を有し、前記試料に外部から磁界を印加することができる磁界印加手段とを備えることを特徴とする近接場偏光顕微鏡である。 The present invention has been made to solve the above problems, and the first invention is a near-field polarization microscope capable of detecting a magnetic domain of a sample having at least a surface having magnetism, and is formed of a nonmagnetic material. The probe has a concave shape that tapers toward the tip. The probe is formed of a dielectric and the inner surface is covered with a metal film, and an atom is formed between the probe and the sample. A cantilever arranged so that an interatomic force acts, a magnetic domain detection optical system capable of detecting a magnetic domain of the sample by near-field light by irradiation of the inner surface of the probe with magnetic domain detection laser light, and a wavelength of the magnetic domain detection laser light An observation illumination optical system capable of observing the irradiation state of the magnetic domain detection laser light by an optical image of the return light from the cantilever of illumination light having a wavelength band other than the above, and the magnetic domain detection optical system and the observation illumination optical system. And an objective lens provided in common, and a magnetic field applying means that has an upper magnetic pole and a lower magnetic pole that are disposed above and below the cantilever and the sample and that can apply a magnetic field to the sample from the outside. This is a near-field polarized light microscope.
　第二発明は、前記試料を２次元平面内で走査させる走査手段と、この走査手段により設定量ずつ前記試料を移動させ、その各点におけるｚ座標を記録する座標記録手段と、設定値間において外部磁界を変動させる磁界変動手段と、前記各点において外部磁界を変動させた際の情報を記憶する記憶手段とをさらに備え、前記磁区検出光学系からの前記情報に基づいて、前記試料の微小領域の磁気ヒステリシスを測定することができることを特徴とする近接場偏光顕微鏡である。 According to a second aspect of the present invention, there is provided a scanning unit that scans the sample in a two-dimensional plane, a coordinate recording unit that moves the sample by a set amount by the scanning unit, and records a z coordinate at each point, and a set value. A magnetic field changing means for changing the external magnetic field; and a storage means for storing information when the external magnetic field is changed at each of the points, and based on the information from the magnetic domain detection optical system, It is a near-field polarization microscope characterized by being able to measure the magnetic hysteresis of a region.
　第三発明は、前記下部磁極の上端部は、上方へ行くに従って先細りに形成されることを特徴とする近接場偏光顕微鏡である。 The third invention is a near-field polarization microscope characterized in that an upper end portion of the lower magnetic pole is tapered toward the upper side.
　第四発明は、前記磁区検出光学系は、消光可能なポラライザを二つ備えることを特徴とする近接場偏光顕微鏡である。 The fourth invention is a near-field polarization microscope characterized in that the magnetic domain detection optical system includes two quenchable polarizers.
　第五発明は、前記ポラライザは、前記試料で反射された前記近接場光とそれ以外の光とを含む光から、前記それ以外の光を消光させて、前記試料で反射された前記近接場光と前記それ以外の光とを分離することができるＧ－Ｔアナライザとされ、前記試料で反射された近接場光と前記それ以外の光とを含む光の進行方向において、一方の前記Ｇ－Ｔアナライザよりも下流側に他方の前記Ｇ－Ｔアナライザが配置され、前記探針と前記試料との間の原子間力が無視できる程度に小さくなるよう前記試料の磁区検出時よりも前記探針が前記試料から離された状態において、前記磁区検出光学系が備える光の検出装置で検出される光が最小となるように一方の前記Ｇ－Ｔアナライザおよび他方の前記Ｇ－Ｔアナライザが調整され、その調整後、前記探針が前記試料に接触されるコンタクト状態、または前記探針と前記試料との間に形成される隙間が維持されるノンコンタクト状態において、他方の前記Ｇ－Ｔアナライザが回転されて前記検出装置で検出される光強度が最小値と最大値との間となるように設定されることを特徴とする近接場偏光顕微鏡である。 In a fifth aspect of the invention, the polarizer is configured to quench the other light from the light including the near-field light reflected by the sample and the other light, and to reflect the near-field light reflected by the sample. And the other light can be separated from each other in the traveling direction of the light including the near-field light reflected by the sample and the other light. The other GT analyzer is arranged on the downstream side of the analyzer, and the probe is smaller than the time of detecting the magnetic domain of the sample so that the atomic force between the probe and the sample becomes so small that it can be ignored. One GT analyzer and the other GT analyzer are adjusted so that the light detected by the light detection device provided in the magnetic domain detection optical system is minimized in a state separated from the sample. After that adjustment, before In the contact state in which the probe is in contact with the sample, or in the non-contact state in which a gap formed between the probe and the sample is maintained, the other GT analyzer is rotated to rotate the detection device. The near-field polarized light microscope is characterized in that the light intensity detected in (1) is set to be between a minimum value and a maximum value.
　第六発明は、前記磁区検出光学系は、前記試料で反射された前記近接場光とそれ以外の光とが含まれる光を、二つの方向の直線偏光成分に分離することができる偏光ビームスプリッタを備え、一方の前記直線偏光成分の光強度と他方の前記直線偏光成分の光強度との差分を、一方の前記直線偏光成分の光強度と他方の前記直線偏光成分の光強度との和分で割ることを特徴とする近接場偏光顕微鏡である。 According to a sixth aspect of the invention, the magnetic domain detection optical system is capable of separating light including the near-field light reflected by the sample and other light into linearly polarized light components in two directions. The difference between the light intensity of one of the linearly polarized light components and the light intensity of the other of the linearly polarized light components is the sum of the light intensity of one of the linearly polarized light components and the light intensity of the other linearly polarized light component. It is a near-field polarization microscope characterized by dividing by.
　第七発明は、前記観察照明光学系は、結像レンズおよびカメラを備え、前記対物レンズ、前記結像レンズおよび前記カメラを備える光学顕微鏡の倍率が約１０００倍とされることを特徴とする近接場偏光顕微鏡である。 According to a seventh aspect of the present invention, the observation illumination optical system includes an imaging lens and a camera, and a magnification of an optical microscope including the objective lens, the imaging lens, and the camera is approximately 1000 times. It is a field polarization microscope.
　さらに、第八発明は、前記磁区検出光学系は、前記試料で反射された前記近接場光とそれ以外の光とを含む光から、前記それ以外の光を消光させて、前記試料で反射された前記近接場光と前記それ以外の光とを分離することができるＧ－Ｔアナライザ一つと、光を検出することができる検出装置とを備え、前記探針と前記試料との間の原子間力が無視できる程度に小さくなるよう前記試料の磁区検出時よりも前記探針が前記試料から離された状態において、前記検出装置で検出される光が最小となるように前記Ｇ－Ｔアナライザが調整され、その調整後、前記探針が前記試料に接触されるコンタクト状態、または前記探針と前記試料との間に形成される隙間が維持されるノンコンタクト状態において、前記試料の磁区の検出が行われることを特徴とする近接場偏光顕微鏡である。 Further, according to an eighth aspect of the invention, the magnetic domain detection optical system is configured to quench the other light from the light including the near-field light reflected by the sample and the other light and reflect the light from the sample. A GT analyzer capable of separating the near-field light and the other light and a detection device capable of detecting the light, and the interatomic space between the probe and the sample. The GT analyzer is configured so that the light detected by the detection device is minimized when the probe is separated from the sample than when the magnetic domain of the sample is detected so that the force is negligibly small. After the adjustment, the magnetic domain of the sample is detected in a contact state where the probe is in contact with the sample or in a non-contact state where a gap formed between the probe and the sample is maintained. Is done A near-field polarizing microscope, characterized.
　第一発明によれば、カンチレバーが非磁性材料から形成されることで、カンチレバーを挟んで上部磁極と下部磁極とが配置される磁界印加手段により、試料に磁界が印加された場合、カンチレバーが磁界印加手段による磁界の影響を受けることがない。従って、試料に外部から磁界を印加しつつ、試料の磁区を正確に検出することができる。また、近接場光を用いることで、光の回折限界を超えた分解能で、試料の磁区を検出することができる。 According to the first invention, when the cantilever is formed of a nonmagnetic material, when the magnetic field is applied to the sample by the magnetic field applying means in which the upper magnetic pole and the lower magnetic pole are arranged with the cantilever interposed therebetween, the cantilever is There is no influence of the magnetic field by the applying means. Therefore, the magnetic domain of the sample can be accurately detected while applying a magnetic field to the sample from the outside. Further, by using near-field light, the magnetic domain of the sample can be detected with a resolution exceeding the diffraction limit of light.
　第二発明によれば、ＡＦＭ像と共に、試料の微小で局所的な磁気ヒステリシスを得ることができる。 According to the second invention, fine and local magnetic hysteresis of the sample can be obtained together with the AFM image.
　第三発明によれば、下部磁極の上端部が先細りに形成されることで、磁界印加手段による磁界をより強くすることができる。 According to the third aspect of the invention, the upper end portion of the lower magnetic pole is tapered, so that the magnetic field by the magnetic field applying means can be further strengthened.
　第四発明によれば、消光可能なポラライザを二つ設けることで、近接場光とそれ以外の光とが含まれる光から、前記それ以外の光がより確実に消光されて、近接場光とそれ以外の光とがより確実に分離され、近接場光の中に含まれる磁区情報をより確実に抽出することができる。 According to the fourth invention, by providing two quenchable polarizers, the other light is more reliably quenched from the light including the near-field light and the other light, and the near-field light and Other light is more reliably separated and the magnetic domain information contained in the near-field light can be extracted more reliably.
　第五発明によれば、ポラライザが消光比の大きなＧ－Ｔアナライザとされることで、計測対象である近接場光とそれ以外の光とをより確実に分離することができ、近接場光の中に含まれる磁区情報をより確実に抽出することができる。 According to the fifth invention, the polarizer is a GT analyzer having a large extinction ratio, so that the near-field light to be measured and the other light can be more reliably separated from each other. The magnetic domain information contained therein can be extracted more reliably.
　第六発明によれば、偏光ビームスプリッタを設けることで、近接場光とそれ以外の光とが含まれる光を二つの方向の直線偏光成分に分離することができる。そして、両直線偏光成分の光強度の差分を両直線偏光成分の光強度の和分で割って規格化することにより、ノイズを抑制して磁気カー効果のみを測定することができる。これにより、近接場光とそれ以外の光とが含まれる光から、計測対象である近接場光の情報をより確実に抽出することができる。すなわち、試料表面の近接場領域の偏向情報を得ることができる。 According to the sixth invention, by providing the polarization beam splitter, it is possible to separate light including near-field light and other light into linearly polarized light components in two directions. Then, by dividing the difference between the light intensities of the two linearly polarized light components by the sum of the light intensities of the two linearly polarized light components, the noise can be suppressed and only the magnetic Kerr effect can be measured. Thereby, it is possible to more reliably extract information on the near-field light that is the measurement target from the light including the near-field light and other light. That is, the deflection information of the near field region on the sample surface can be obtained.
　第七発明によれば、光学顕微鏡の倍率を約１０００倍の高倍率にすることで、試料の観察位置と、磁区検出レーザ光の探針への照射位置とをモニタすることができる。これにより、試料の磁区の検出精度を向上させることができる。 According to the seventh invention, the observation position of the sample and the irradiation position of the magnetic domain detection laser light on the probe can be monitored by setting the magnification of the optical microscope to a high magnification of about 1000 times. Thereby, the detection accuracy of the magnetic domain of a sample can be improved.
　さらに、第八発明によれば、さらに簡易な構成および方法で、近接場光とそれ以外の光とが含まれる光から、前記それ以外の光が消光されて、近接場光とそれ以外の光とが分離され、近接場光の中に含まれる磁区情報を抽出することができる。 Further, according to the eighth invention, with the simpler configuration and method, the other light is quenched from the light including the near-field light and the other light, and the near-field light and the other light are extinguished. And the magnetic domain information included in the near-field light can be extracted.
本発明の近接場偏光顕微鏡の一実施例を示す概略構成図である。It is a schematic block diagram which shows one Example of the near field polarizing microscope of this invention. 図１の近接場偏光顕微鏡の一部を拡大して示す概略図である。It is the schematic which expands and shows a part of near field polarizing microscope of FIG. 図１の近接場偏光顕微鏡の変形例の磁界印加手段を示す概略側面図である。It is a schematic side view which shows the magnetic field application means of the modification of the near-field polarizing microscope of FIG. 図３の磁界印加手段の概略平面図である。It is a schematic plan view of the magnetic field application means of FIG. 図１の近接場偏光顕微鏡の別の変形例を示す概略構成図である。It is a schematic block diagram which shows another modification of the near-field polarizing microscope of FIG. 図１の近接場偏光顕微鏡の他の変形例を示す概略構成図である。It is a schematic block diagram which shows the other modification of the near-field polarizing microscope of FIG. 図１の近接場偏光顕微鏡のさらに別の変形例を示す概略構成図である。It is a schematic block diagram which shows another modification of the near-field polarizing microscope of FIG.
　以下、本発明の具体的実施例を図面に基づいて詳細に説明する。 Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
　図１および図２は、本発明の近接場偏光顕微鏡の一実施例を示す図であり、図１は、一部を断面にして示す概略構成図、図２は、図１の一部を拡大した概略図であり、さらに一部を拡大して示している。本実施例の近接場偏光顕微鏡１は、探針２を有するカンチレバー３と、磁区検出光学系４と、観察照明光学系５と、磁区検出光学系４および観察照明光学系５に共通の対物レンズ６と、磁界印加手段７とを備える。本実施例では、磁性体から形成される試料８の磁区を検出する場合について説明するが、試料８はこれに限定されるものではなく、少なくとも表面が磁性を有していればよい。 1 and 2 are diagrams showing an embodiment of the near-field polarization microscope of the present invention. FIG. 1 is a schematic configuration diagram showing a part thereof in cross section, and FIG. 2 is an enlarged part of FIG. It is a schematic diagram and a part is further enlarged and shown. The near-field polarization microscope 1 of the present embodiment includes a cantilever 3 having a probe 2, a magnetic domain detection optical system 4, an observation illumination optical system 5, an objective lens common to the magnetic domain detection optical system 4 and the observation illumination optical system 5. 6 and magnetic field applying means 7. In this embodiment, the case where the magnetic domain of the sample 8 formed from a magnetic material is detected will be described. However, the sample 8 is not limited to this, and it is sufficient that at least the surface has magnetism.
　カンチレバー３は、光を透過する材料で非磁性かつ非導電性材料から形成され、本実施例では窒化シリコンから形成される。図２に示されるように、カンチレバー３は、一端支持型構成とされ、板状の梁部９と、梁部９の他端部に設けられる探針２とを有して構成される。カンチレバー３は、一端側（探針２が形成される側と反対側）を支点として撓曲可能とされる。また、カンチレバー３は、誘電体とされており、本実施例では、たとえば、ＳｉＯ２、Ｓｉ３Ｎ４、ＳｉＮなどとされる。 The cantilever 3 is made of a non-magnetic and non-conductive material that transmits light, and is made of silicon nitride in this embodiment. As shown in FIG. 2, the cantilever 3 has a one-end support type configuration and includes a plate-like beam portion 9 and a probe 2 provided at the other end portion of the beam portion 9. The cantilever 3 can be bent with one end side (the side opposite to the side where the probe 2 is formed) as a fulcrum. Further, the cantilever 3 is a dielectric, and in this embodiment, for example, SiO 2 , Si 3 N 4 , SiN or the like is used.
　カンチレバー３の探針２は、先端へ行くに従って先細りとなる凹形状とされ、本実施例では逆円錐状に形成される。探針２の形状は、逆円錐状に限定されるものではなく、たとえば、逆角錐状に形成してもよい。探針２の先端には、貫通穴が形成されていない。探針２の内面全体には、表面プラズモン共鳴が起きるように、金属製の膜１０が形成される。本実施例では、膜１０は、金、銀、アルミなどの金属を用いて、金属蒸着により形成される。 The probe 2 of the cantilever 3 has a concave shape that tapers toward the tip, and is formed in an inverted conical shape in this embodiment. The shape of the probe 2 is not limited to an inverted conical shape, and may be formed in an inverted pyramid shape, for example. A through hole is not formed at the tip of the probe 2. A metal film 10 is formed on the entire inner surface of the probe 2 so that surface plasmon resonance occurs. In this embodiment, the film 10 is formed by metal vapor deposition using a metal such as gold, silver, or aluminum.
　磁区検出光学系４は、試料８の磁区を検出するものである。磁区検出光学系４は、磁区検出レーザ光１１のレーザ光源１２と、レーザ光源１２からの磁区検出レーザ光１１の絞り１３と、λ／２板１４と、λ／４板１５と、ダイクロイックミラー１６とを備える。図１に示されるように、磁区検出レーザ光１１の光路に沿って、レーザ光源１２から近い順に、絞り１３、λ／２板１４、λ／４板１５およびダイクロイックミラー１６が配置される。なお、本実施例では、磁区検出レーザ光１１は、たとえば、６３３ｎｍの赤の波長とされる。磁区検出レーザ光１１の波長は、これに限定されるものではなく、カンチレバーのプラズモン共鳴波長付近の波長とすればよい。 The magnetic domain detection optical system 4 detects the magnetic domain of the sample 8. The magnetic domain detection optical system 4 includes a laser light source 12 for the magnetic domain detection laser light 11, a diaphragm 13 for the magnetic domain detection laser light 11 from the laser light source 12, a λ / 2 plate 14, a λ / 4 plate 15, and a dichroic mirror 16. With. As shown in FIG. 1, an aperture 13, a λ / 2 plate 14, a λ / 4 plate 15, and a dichroic mirror 16 are arranged in the order closer to the laser light source 12 along the optical path of the magnetic domain detection laser beam 11. In the present embodiment, the magnetic domain detection laser light 11 has a red wavelength of 633 nm, for example. The wavelength of the magnetic domain detection laser beam 11 is not limited to this, and may be a wavelength near the plasmon resonance wavelength of the cantilever.
　また、磁区検出光学系４は、試料８の磁区が検出される検出装置１７と、狭帯域干渉フィルタ１８と、レンズ１９と、Ｇ－Ｔ（Ｇｌａｎ－Ｔｈｏｍｐｓｏｎ）アナライザ２０が一つと、λ／４板２１と、検出装置１７への不要光が排除される不要光排除手段２２とをさらに備える。狭帯域干渉フィルタ１８は、特定の波長の光のみを通すフィルタとされ、周囲の蛍光灯などの不要な光がカットされて、レーザ光のみを通すことができる。検出装置１７は、光の試料８への照射による試料８からの戻り光により、試料８の磁区を検出することができる。また、検出装置１７は、光を検出することができるものであり、導入される試料８からの戻り光の態様、目的とする検出信号態様などに応じて、たとえば、フォトダイオード、光電子増倍管（フォトマルチプライヤ）、分光器などによって構成される。なお、狭帯域干渉フィルタ１８が用いられる場合には、検出装置１７は光電子増倍管とされる。不要光排除手段２２は、探針２の先端との共焦点を形成する一対の共焦点レンズ２３と、共焦点レンズ２３間に配置されるアパーチャ２４とを備えることで、探針２先端付近の焦点領域のみの光を限定取得しそれ以外の光を排除することができる。Ｇ－Ｔアナライザ２０は、試料８の近接場光とそれ以外の光とを含む光から、前記それ以外の光を消光させて、試料８の近接場光とそれ以外の光とを分離することができるものである。 The magnetic domain detection optical system 4 includes a detection device 17 that detects the magnetic domain of the sample 8, a narrow band interference filter 18, a lens 19, and a GT (Glan-Thompson) analyzer 20, and λ / 4. It further includes a plate 21 and unnecessary light eliminating means 22 for eliminating unnecessary light to the detection device 17. The narrow band interference filter 18 is a filter that passes only light of a specific wavelength, and unnecessary light such as a surrounding fluorescent lamp is cut off, and only the laser light can pass. The detection device 17 can detect the magnetic domain of the sample 8 by the return light from the sample 8 due to the irradiation of the sample 8 with light. The detection device 17 is capable of detecting light. For example, a photodiode or a photomultiplier tube is used depending on the mode of return light from the sample 8 to be introduced, the target detection signal mode, and the like. (Photomultiplier), a spectroscope, and the like. When the narrow band interference filter 18 is used, the detection device 17 is a photomultiplier tube. The unnecessary light eliminating means 22 includes a pair of confocal lenses 23 that form a confocal point with the tip of the probe 2 and an aperture 24 that is disposed between the confocal lenses 23, so that the vicinity of the tip of the probe 2. It is possible to obtain limited light only in the focal region and exclude other light. The GT analyzer 20 separates the near-field light of the sample 8 and the other light by quenching the other light from the light including the near-field light of the sample 8 and the other light. It is something that can be done.
　観察照明光学系５は、カンチレバー３に対する磁区検出レーザ光１１の照射状態や、探針２と試料８との位置関係などを観察するものである。観察照明光学系５は、照明光源２５と、ビームスプリッタ２６と、結像レンズ２７と、試料８からの戻り光の光学像が観察される観察装置２８とを備える。照明光源２５は、たとえば、白色の照明光２９を発生させる白色光源とされる。ビームスプリッタ２６は、照明光源２５からの照明光２９を、後述する対物レンズ６の光軸もしくは近軸上に導入するためのものとされる。観察装置２８は、カメラ３０と、撮像光学像が映し出されるモニタ３１とを備える。このような観察照明光学系５と磁区検出光学系４とに共通の対物レンズ６は、試料８の最も近くに配置されるレンズとされる。 The observation illumination optical system 5 observes the irradiation state of the magnetic domain detection laser beam 11 on the cantilever 3 and the positional relationship between the probe 2 and the sample 8. The observation illumination optical system 5 includes an illumination light source 25, a beam splitter 26, an imaging lens 27, and an observation device 28 that observes an optical image of the return light from the sample 8. The illumination light source 25 is, for example, a white light source that generates white illumination light 29. The beam splitter 26 is used for introducing illumination light 29 from the illumination light source 25 onto the optical axis or paraxial axis of the objective lens 6 described later. The observation device 28 includes a camera 30 and a monitor 31 on which an imaging optical image is projected. The objective lens 6 common to the observation illumination optical system 5 and the magnetic domain detection optical system 4 is a lens disposed closest to the sample 8.
　前述したように、磁区検出レーザ光１１は、赤のレーザ光とされる。照明光源２５は、磁区検出レーザ光１１の波長以外の波長に渡る波長帯、本実施例では赤の波長以外の波長に渡る波長帯とされ、照明光２９として好適な白色光の照明光２９の白色光源とされる。 As described above, the magnetic domain detection laser beam 11 is a red laser beam. The illumination light source 25 has a wavelength band extending over a wavelength other than the wavelength of the magnetic domain detection laser beam 11, and a wavelength band extending over a wavelength other than the red wavelength in this embodiment. A white light source is used.
　磁界印加手段７は、試料８に外部から磁界を印加するものである。図１に示されるように、磁界印加手段７は、基体３２と、基体３２に設けられるコイル３３とを備える。基体３２は、本体３４と、本体３４の上端部に設けられる蓋体３５とを有して構成される。本体３４は、円柱状で上端部が上方へ行くに従って先細りとなる円錐台状の強磁性体から形成される鉄心３６と、鉄心３６との間に筒状隙間３７を形成するよう配置される円筒状の筒部３８と、鉄心３６の下端部と筒部３８の下端部とが接続される円板状の接続部３９とを有する。ここで、鉄心３６および筒部３８はそれぞれ、接続部３９にネジで固定される。 The magnetic field applying means 7 applies a magnetic field to the sample 8 from the outside. As shown in FIG. 1, the magnetic field applying means 7 includes a base body 32 and a coil 33 provided on the base body 32. The base 32 includes a main body 34 and a lid 35 provided at the upper end of the main body 34. The main body 34 is a cylinder and is a cylinder arranged so as to form a cylindrical gap 37 between the iron core 36 and an iron core 36 formed from a truncated cone-shaped ferromagnetic material whose upper end portion tapers upward. And a disk-shaped connecting portion 39 to which the lower end portion of the iron core 36 and the lower end portion of the cylindrical portion 38 are connected. Here, each of the iron core 36 and the cylindrical portion 38 is fixed to the connecting portion 39 with screws.
　蓋体３５は、円板状に形成され、一部に切欠き部４０が形成される。蓋体３５の下面の縁部には、下方へ筒状に延出して載置部４１が形成される。蓋体３５の中央部には、板面を貫通して円形状の導入穴４２が形成され、この導入穴４２と切欠き部４０とは連通している。コイル３３は、前記筒状隙間３７に配置される。蓋体３５の載置部４１は、本体３４の筒部３８の上面にネジで固定される。これにより、蓋体３５が上部磁極４３とされる一方、基体３２の鉄心３６が下部磁極４４とされる。上部磁極４３と下部磁極４４との間には、蓋体３５の載置部４１によって間隔が形成される。蓋体３５の載置部４１には、蓋体３５の切欠き部４０と径方向に対向する位置において、周方向へ沿って貫通穴４５が形成される。 The lid 35 is formed in a disk shape, and a notch 40 is formed in part. On the edge of the lower surface of the lid body 35, a mounting portion 41 is formed extending downward in a cylindrical shape. A circular introduction hole 42 is formed in the central portion of the lid 35 so as to penetrate the plate surface, and the introduction hole 42 and the cutout portion 40 communicate with each other. The coil 33 is disposed in the cylindrical gap 37. The mounting portion 41 of the lid body 35 is fixed to the upper surface of the cylindrical portion 38 of the main body 34 with screws. As a result, the lid 35 is the upper magnetic pole 43, while the iron core 36 of the base body 32 is the lower magnetic pole 44. A space is formed between the upper magnetic pole 43 and the lower magnetic pole 44 by the mounting portion 41 of the lid 35. A through hole 45 is formed in the mounting portion 41 of the lid 35 along the circumferential direction at a position facing the notch 40 of the lid 35 in the radial direction.
　導入穴４２の直径や厚さは、対物レンズ６の作動距離や焦点、その他開口数（ＮＡ）に合わせて適宜に設定される。また、導入穴４２の形状は、円形に限定されるものではなく、対物レンズ６の作動距離や焦点、開口数に合わせて適宜に変更可能とされる。これにより、本実施例の磁界印加手段７の構成であっても、大きな開口数や短焦点を実現することができる。 The diameter and thickness of the introduction hole 42 are appropriately set according to the working distance and focus of the objective lens 6 and other numerical aperture (NA). Further, the shape of the introduction hole 42 is not limited to a circular shape, and can be appropriately changed according to the working distance, the focal point, and the numerical aperture of the objective lens 6. Thereby, even if it is the structure of the magnetic field application means 7 of a present Example, a large numerical aperture and a short focus are realizable.
　なお、本実施例の近接場偏光顕微鏡１は、前述した他、ダイクロイックミラー４６と、探針支持片４７が設けられる探針ステージ４８と、試料支持片４９が設けられる試料ステージ５０と、試料スキャナ５１とをさらに備える。図示例では、試料スキャナ５１上に試料ステージ５０が設けられるが、これとは逆に、試料ステージ５０上に試料スキャナ５１を設けてもよい。 The near-field polarizing microscope 1 according to the present embodiment includes a dichroic mirror 46, a probe stage 48 provided with a probe support piece 47, a sample stage 50 provided with a sample support piece 49, and a sample scanner. 51 is further provided. In the illustrated example, the sample stage 50 is provided on the sample scanner 51, but conversely, the sample scanner 51 may be provided on the sample stage 50.
　ダイクロイックミラー４６は、磁区検出レーザ光１１の波長光、本実施例では６３３ｎｍの赤の光を反射させることができる。この際、赤の光の一部は、ダイクロイックミラー４６を通過する。このようにして光強度が減衰されつつ透過された赤の光によって、眩しさが和らげられたビームスポットを視認することができ、これにより、赤のビーム位置をカメラでモニタすることができる。また、ダイクロイックミラー４６は、磁区検出レーザ光１１の波長以外の波長光が透過され、照明光２９を磁区検出レーザ光１１と共に対物レンズ６へ向かわせる波長選択性を有する。試料ステージ５０は、試料スキャナ５１により、近接場偏光顕微鏡１の光軸方向へ沿うｚ軸方向と、これと直交する面上において互いに直交するｘ軸およびｙ軸方向とへ移動可能とされる。 The dichroic mirror 46 can reflect the wavelength light of the magnetic domain detection laser beam 11, which is red light of 633 nm in this embodiment. At this time, part of the red light passes through the dichroic mirror 46. In this way, it is possible to visually recognize the beam spot with the glare reduced by the transmitted red light while the light intensity is attenuated, and the position of the red beam can be monitored by the camera. Further, the dichroic mirror 46 has a wavelength selectivity that allows light having a wavelength other than the wavelength of the magnetic domain detection laser light 11 to pass therethrough and directs the illumination light 29 together with the magnetic domain detection laser light 11 toward the objective lens 6. The sample stage 50 can be moved by the sample scanner 51 in the z-axis direction along the optical axis direction of the near-field polarization microscope 1 and in the x-axis and y-axis directions orthogonal to each other on a plane orthogonal to the z-axis direction.
　ところで、探針２と試料８との間に原子間力が作用するように、探針２の先端が試料８の表面に近接するようカンチレバー３が配置される。図２に示されるように、カンチレバー３は、水晶振動子５２に設けられる。水晶振動子５２は、２本の振動片５３の内、一方を切断したものとされ、残された他方の振動片５３に、カンチレバー３が接着される。水晶振動子５２は、セラミック製のベース５４を介して探針ホルダ５６に設けられ、この探針ホルダ５６は、探針支持片４７に設けられる。探針ホルダ５６および探針支持片４７は、非磁性かつ非導電性材料から形成され、本実施例では、アルミナなどのセラミック製とされる。探針支持片４７は、細長い板状に形成され、先端部に探針ホルダ５６が設けられる。この探針支持片４７は、先端部が蓋体３５の切欠き部４０を介して基体３２内に差し込まれる。この際、カンチレバー３は、上部磁極４３と下部磁極４４との間に配置されると共に、探針２が蓋体３５の導入穴４２に対応して配置される。 Incidentally, the cantilever 3 is arranged so that the tip of the probe 2 is close to the surface of the sample 8 so that an atomic force acts between the probe 2 and the sample 8. As shown in FIG. 2, the cantilever 3 is provided in the crystal resonator 52. The crystal resonator 52 is formed by cutting one of the two vibrating pieces 53, and the cantilever 3 is bonded to the remaining vibrating piece 53. The crystal unit 52 is provided on the probe holder 56 via a ceramic base 54, and the probe holder 56 is provided on the probe support piece 47. The probe holder 56 and the probe support piece 47 are made of a nonmagnetic and nonconductive material, and are made of ceramic such as alumina in this embodiment. The probe support piece 47 is formed in an elongated plate shape, and a probe holder 56 is provided at the tip. The tip of the probe support piece 47 is inserted into the base 32 through the notch 40 of the lid 35. At this time, the cantilever 3 is arranged between the upper magnetic pole 43 and the lower magnetic pole 44, and the probe 2 is arranged corresponding to the introduction hole 42 of the lid 35.
　一方、試料８は、試料ホルダ５７を介して、試料支持片４９に設けられる。試料ホルダ５７および試料支持片４９は、非磁性かつ非導電性材料から形成され、本実施例では、アルミナなどのセラミック製とされる。試料支持片４９は、細長い板状に形成され、先端部に試料ホルダ５７が設けられる。この試料支持片４９は、蓋体３５に形成された貫通穴４５を介して、基体３２内に差し込まれる。この際、試料８は、カンチレバー３の下側において、上部磁極４３と下部磁極４４との間に配置されると共に、蓋体３５の導入穴４２に対応して配置される。 On the other hand, the sample 8 is provided on the sample support piece 49 via the sample holder 57. The sample holder 57 and the sample support piece 49 are made of a nonmagnetic and nonconductive material, and are made of ceramic such as alumina in this embodiment. The sample support piece 49 is formed in an elongated plate shape, and a sample holder 57 is provided at the tip. The sample support piece 49 is inserted into the base body 32 through a through hole 45 formed in the lid body 35. At this time, the sample 8 is disposed below the cantilever 3 between the upper magnetic pole 43 and the lower magnetic pole 44 and corresponding to the introduction hole 42 of the lid 35.
　次に、本実施例の近接場偏光顕微鏡１を用いて試料８の磁区を検出する動作について説明する。ここで、近接場光について説明する。レーザ光源１２から照射される磁区検出レーザ光１１のファーフィールド光を探針２の先端にフォーカスさせることで、探針２と膜１０との境界面でプラズモン共鳴が励起され、これが先端に貫通穴が形成されていない探針２の先端側へ伝播し、先端から近接場光（ニアフィールド光）が発生し、近接場光が試料８に照射される。この近接場光によるスポット径は回折限界に規制されず、対物レンズ６の開口数および磁区検出レーザ光１１の波長に依存しないことから、微小な照射スポット径とすることができる。 Next, the operation of detecting the magnetic domain of the sample 8 using the near-field polarizing microscope 1 of this embodiment will be described. Here, the near-field light will be described. By focusing the far field light of the magnetic domain detection laser light 11 irradiated from the laser light source 12 on the tip of the probe 2, plasmon resonance is excited at the interface between the probe 2 and the film 10, and this is a through hole at the tip. Is propagated to the tip side of the probe 2 where no is formed, near-field light (near-field light) is generated from the tip, and the near-field light is irradiated to the sample 8. The spot diameter due to the near-field light is not restricted by the diffraction limit, and does not depend on the numerical aperture of the objective lens 6 and the wavelength of the magnetic domain detection laser light 11, so that it can be a very small irradiation spot diameter.
　試料８には、磁界印加手段７によって、外部から磁界が印加される。具体的には、コイル３３に電流を流すことで、蓋体３５および鉄心３６がそれぞれ磁極４３，４４となり、磁界を発生させることができる。これにより、本実施例では、強磁界、たとえば１テスラの磁界を発生させることができる。このようにして、外部から磁界を印加しつつ、試料８の磁区を検出することができる。 A magnetic field is applied to the sample 8 from the outside by the magnetic field applying means 7. Specifically, by applying a current to the coil 33, the lid 35 and the iron core 36 become magnetic poles 43 and 44, respectively, and a magnetic field can be generated. Thereby, in a present Example, a strong magnetic field, for example, a 1 Tesla magnetic field, can be generated. In this way, the magnetic domain of the sample 8 can be detected while applying a magnetic field from the outside.
　近接場偏光顕微鏡１では、照明光２９は、ビームスプリッタ２６で反射され、ダイクロイックミラー４６を通過した後に対物レンズ６にて集光され、蓋体３５の導入穴４２を介して、カンチレバー３および試料８に照射される。カンチレバー３および試料８に照射された照明光２９の戻り光は、レンズ２７を通過して、観察装置２８により観察される。この観察結果に基づいて、試料８の基準位置の調整が試料スキャナ５１によって行われる。試料スキャナ５１は、ｘｙ方向（水平方向）およびｚ方向（垂直方向）に、試料ステージ５０を移動させることができる。なお、必要に応じて、カンチレバー３の設定位置の調整が行われる。 In the near-field polarizing microscope 1, the illumination light 29 is reflected by the beam splitter 26, passes through the dichroic mirror 46, is collected by the objective lens 6, and is passed through the introduction hole 42 of the lid 35 and the cantilever 3 and the sample. 8 is irradiated. The return light of the illumination light 29 applied to the cantilever 3 and the sample 8 passes through the lens 27 and is observed by the observation device 28. Based on the observation result, the reference position of the sample 8 is adjusted by the sample scanner 51. The sample scanner 51 can move the sample stage 50 in the xy direction (horizontal direction) and the z direction (vertical direction). Note that the setting position of the cantilever 3 is adjusted as necessary.
　その後、試料スキャナ５１により試料ステージ５０がｘ方向およびｙ方向に移動され、磁区検出レーザ光１１による探針２先端からの近接場光のスポットが、試料８の表面上に走査される。このようにして、カンチレバー３を固定した状態で、試料８を移動させる。磁区検出レーザ光１１は、絞り１３を介してλ／２板１４を通過した後、さらにλ／４板１５を通過する。この際、磁区検出レーザ光１１は、λ／２板１４により入射された直線偏光が回転され、λ／４板１５により円偏光または楕円偏光とされる。円偏光のファーフィールド光は、ダイクロイックミラー１６を通過し、ミラー５８およびミラー５９にて反射された後、ダイクロイックミラー４６で反射されて対物レンズ６にて集光され、蓋体３５の導入穴４２を介して探針２の先端にフォーカスされ、これにより先端から近接場光が得られ、その近接場光が試料８に照射される。 Thereafter, the sample stage 50 is moved in the x and y directions by the sample scanner 51, and the spot of the near-field light from the tip of the probe 2 by the magnetic domain detection laser beam 11 is scanned on the surface of the sample 8. In this way, the sample 8 is moved while the cantilever 3 is fixed. The magnetic domain detection laser beam 11 passes through the λ / 2 plate 14 through the diaphragm 13 and then passes through the λ / 4 plate 15. At this time, in the magnetic domain detection laser light 11, the linearly polarized light incident by the λ / 2 plate 14 is rotated, and is converted into circularly polarized light or elliptically polarized light by the λ / 4 plate 15. The circularly polarized far-field light passes through the dichroic mirror 16, is reflected by the mirror 58 and the mirror 59, is reflected by the dichroic mirror 46, is collected by the objective lens 6, and is introduced into the introduction hole 42 of the lid 35. The near-field light is obtained from the tip, and the sample 8 is irradiated with the near-field light.
　探針２の凹部の底部にフォーカスされる際、磁区検出レーザ光１１の波長の半分以下の内径では、空間を伝播する通常の光（回折光、ファーフィールド光）は、透過せずに反射される。この部分より先端側には、近接場光のみが伝播される。探針２と膜１０との境界面でプラズモン共鳴が励起され、これが探針２の先端方向へ伝播され、探針２の先端から近接場光が滲み出る。この際、探針２の先端部が試料８の表面に近接されていることで、この微小スポットの近接場光が試料８の表面に照射される。 When focusing on the bottom of the concave portion of the probe 2, normal light (diffracted light, far field light) propagating through the space is reflected without being transmitted at an inner diameter less than half the wavelength of the magnetic domain detection laser beam 11. The Only near-field light is propagated to the tip side from this portion. Plasmon resonance is excited at the interface between the probe 2 and the film 10, and this is propagated toward the tip of the probe 2, and near-field light oozes out from the tip of the probe 2. At this time, since the tip of the probe 2 is close to the surface of the sample 8, the near-field light of this minute spot is irradiated onto the surface of the sample 8.
　試料８に照射された近接場光は、試料８の表面の戻り光として、対物レンズ６を通過し、ダイクロイックミラー４６で反射された後、ミラー５９およびミラー５８にて反射され、さらにダイクロイックミラー１６にて反射される。そして、磁区検出光学系４に備えられる検出装置１７によって、試料８表面の磁区などの存在による偏光回転が光強度変化として検出され、試料８の磁区が検出される。 The near-field light irradiated on the sample 8 passes through the objective lens 6 as reflected light on the surface of the sample 8, is reflected by the dichroic mirror 46, is reflected by the mirror 59 and the mirror 58, and is further reflected by the dichroic mirror 16. Reflected at Then, the detection device 17 provided in the magnetic domain detection optical system 4 detects the polarization rotation due to the presence of the magnetic domain on the surface of the sample 8 as a change in light intensity, and detects the magnetic domain of the sample 8.
　試料８の表面から磁区を検出するには、磁気カー効果を検出する必要がある。試料８にて近接場光が反射されると、試料８の磁化の向きに応じて偏光面が回転される。このような戻り光は、前述したように対物レンズ６からダイクロイックミラー１６へ進み、さらに不要光排除手段２２を介して、λ／４板２１へ進む。この際、探針２の内面で反射された不要のファーフィールド光の戻り光もまた、近接場光の戻り光と同様に対物レンズ６からダイクロイックミラー１６へ進み、さらに不要光排除手段２２を介して、λ／４板２１へ進む。 In order to detect a magnetic domain from the surface of the sample 8, it is necessary to detect the magnetic Kerr effect. When the near-field light is reflected by the sample 8, the polarization plane is rotated according to the magnetization direction of the sample 8. Such return light travels from the objective lens 6 to the dichroic mirror 16 as described above, and further travels to the λ / 4 plate 21 via the unnecessary light exclusion means 22. At this time, the return light of unnecessary far-field light reflected by the inner surface of the probe 2 also travels from the objective lens 6 to the dichroic mirror 16 in the same manner as the return light of near-field light, and further passes through the unnecessary light exclusion means 22. Then, the process proceeds to the λ / 4 plate 21.
　試料８からの戻り光と、探針２の内面で反射された不要のファーフィールド光の戻り光とは、λ／４板２１までの光路長が異なる。これにより、λ／４板２１にて直線偏光とされた双方の戻り光は、偏光面の角度が相違した状態で、Ｇ－Ｔアナライザ２０に導入される。なお、Ｇ－Ｔアナライザ２０は、試料８の磁区検出前に調整がなされている。具体的には、Ｇ－Ｔアナライザ２０は、試料８の磁区検出時よりも探針２が試料８から離された状態（探針２を試料８表面から原子間力が無視できる程度に小さくなる位置まで離した状態）において、検出装置１７で検出される光が最小となるように調整されている。本実施例では、探針２が試料８から２０ｎｍ以上離されて、探針２と試料８との間の原子間力が小さい状態で、検出装置１７で検出される光がほぼゼロあるいは最小値になるようＧ－Ｔアナライザが回転されて調整されている。この調整後に、探針２が試料８に接触されたコンタクト状態、または探針２と試料８との間に形成される隙間が維持されたノンコンタクト状態とされて原子間力が一定に制御され、試料８の磁区検出が行われる。この際、Ｇ－Ｔアナライザ２０の偏光角を上記のように調整しておくことで、反射された近接場光のみを取り出すことができる。これの他に、検出装置１７で検出される光強度が最小値と最大値との間となるように、Ｇ－Ｔアナライザ２０の偏光角を調整してもよい。この偏光角の調整は、たとえば、検出装置１７で検出される光がほぼゼロとなるように調整された状態から、Ｇ－Ｔアナライザ２０を約４５度回転させることでなされる。以上のようにして、探針２の内面で反射された不要のファーフィールド光の戻り光が排除され、このようにして導かれた光のみが、レンズ１９と狭帯域干渉フィルタ１８とを介して検出装置１７へ導入され、電気信号に変換した出力を取り出すことができる。 The return light from the sample 8 and the return light of unnecessary far-field light reflected from the inner surface of the probe 2 have different optical path lengths to the λ / 4 plate 21. As a result, both return lights converted into linearly polarized light by the λ / 4 plate 21 are introduced into the GT analyzer 20 with the angles of the polarization planes being different. The GT analyzer 20 is adjusted before the magnetic domain of the sample 8 is detected. Specifically, the GT analyzer 20 is in a state in which the probe 2 is separated from the sample 8 than when the magnetic domain of the sample 8 is detected (the probe 2 is smaller than the surface of the sample 8 so that the atomic force can be ignored). In the state of being separated to the position), the light detected by the detection device 17 is adjusted to be minimum. In the present embodiment, the probe 2 is separated from the sample 8 by 20 nm or more and the atomic force between the probe 2 and the sample 8 is small, and the light detected by the detection device 17 is almost zero or the minimum value. The GT analyzer is rotated and adjusted so that After this adjustment, the atomic force is controlled to be constant by setting the probe 2 in contact with the sample 8 or in the non-contact state in which the gap formed between the probe 2 and the sample 8 is maintained. The magnetic domain detection of the sample 8 is performed. At this time, by adjusting the polarization angle of the GT analyzer 20 as described above, it is possible to extract only the reflected near-field light. In addition to this, the polarization angle of the GT analyzer 20 may be adjusted so that the light intensity detected by the detection device 17 is between the minimum value and the maximum value. This adjustment of the polarization angle is performed, for example, by rotating the GT analyzer 20 by about 45 degrees from a state in which the light detected by the detection device 17 is adjusted to be substantially zero. As described above, the return light of unnecessary far-field light reflected by the inner surface of the probe 2 is eliminated, and only the light thus guided passes through the lens 19 and the narrowband interference filter 18. An output introduced into the detection device 17 and converted into an electric signal can be taken out.
　不要光排除手段２２では、一対の共焦点レンズ２３，２３による共焦点関係にない回折光を、共焦点位置に配置されるアパーチャ２４によって遮断してカットすることができる。不要光排除手段２２では、たとえば、探針２からの信号を検出する場合、アパーチャ２４のピンホールの径は、その信号のみを検出できるように、共焦点レンズ２３の焦点距離と対物レンズ６の焦点距離との比と、探針２先端付近の観測したい範囲が決まることで設定される。 In the unnecessary light exclusion means 22, diffracted light that is not in a confocal relationship by the pair of confocal lenses 23, 23 can be cut off by being cut off by the aperture 24 arranged at the confocal position. For example, when the signal from the probe 2 is detected by the unnecessary light exclusion unit 22, the diameter of the pinhole of the aperture 24 is the same as the focal length of the confocal lens 23 and the objective lens 6 so that only the signal can be detected. It is set by determining the ratio to the focal length and the range to be observed near the tip of the probe 2.
　ところで、カンチレバー３は、探針２と試料８との間の距離が一定となるように制御される。図１および図２に示されるように、カンチレバー３が設けられる水晶振動子５２には、図示しないが、加振用電極や検出用電極が設けられる。この加振用電極に交流電圧が印加されることで、水晶振動子５２の振動片５３が屈曲振動され、これにより、カンチレバー３の探針２を試料８の表面と略垂直な方向に振動させることができる。 By the way, the cantilever 3 is controlled so that the distance between the probe 2 and the sample 8 is constant. As shown in FIGS. 1 and 2, the crystal resonator 52 provided with the cantilever 3 is provided with an excitation electrode and a detection electrode (not shown). When an alternating voltage is applied to the excitation electrode, the vibrating piece 53 of the crystal resonator 52 is flexibly vibrated, thereby causing the probe 2 of the cantilever 3 to vibrate in a direction substantially perpendicular to the surface of the sample 8. be able to.
　試料スキャナ５１は、探針２と試料８との間の距離を調整できる微動手段と、探針２と試料８とを２次元平面内で相対的に走査する走査手段とを備えて構成される。この試料スキャナ５１と試料ステージ５０とは接続されており、これにより、試料ステージ５０、ひいては試料８が、試料スキャナ５１によりｘｙ方向（水平方向）およびｚ方向（垂直方向）へ移動可能とされる。 The sample scanner 51 includes fine movement means that can adjust the distance between the probe 2 and the sample 8, and scanning means that relatively scans the probe 2 and the sample 8 in a two-dimensional plane. . The sample scanner 51 and the sample stage 50 are connected, so that the sample stage 50 and eventually the sample 8 can be moved by the sample scanner 51 in the xy direction (horizontal direction) and the z direction (vertical direction). .
　水晶振動子５２に交流電圧が印加されて振動片５３が共振された状態で、探針２の先端と試料８の表面とが近接される。これにより、探針２の先端と試料８の表面との間に原子間力が作用され、振動片５３の周波数や振幅などの振動状態が変化し、水晶振動子５２の振動により発生する圧電電流が変化される。なお、水晶振動子５２先端にカンチレバー３を取り付ける場合、カンチレバー３自身の共振周波数が水晶振動子５２よりも小さいと、原子間力が検出し難くなるので、水晶振動子５２よりも共振周波数が高くなるように短く取り付けられる。このようにして、水晶振動子５２にカンチレバー３を取り付ける場合には、カンチレバー３の共振周波数が水晶振動子５２よりも小さくされる。 The tip of the probe 2 and the surface of the sample 8 are brought close to each other in a state in which an alternating voltage is applied to the crystal unit 52 and the resonator element 53 is resonated. As a result, an atomic force acts between the tip of the probe 2 and the surface of the sample 8, and the vibration state such as the frequency and amplitude of the vibrating piece 53 changes, and the piezoelectric current generated by the vibration of the quartz crystal resonator 52. Is changed. When the cantilever 3 is attached to the tip of the crystal resonator 52, if the resonance frequency of the cantilever 3 itself is smaller than that of the crystal resonator 52, it becomes difficult to detect the atomic force, so the resonance frequency is higher than that of the crystal resonator 52. It is attached so as to be short. In this way, when the cantilever 3 is attached to the crystal resonator 52, the resonance frequency of the cantilever 3 is made smaller than that of the crystal resonator 52.
　水晶振動子５２の検出用電極には、プリアンプ６０を介して、ＰＬＬ（Phase Locked Loop）回路６１が接続される。プリアンプ６０では、水晶振動子５２の振動により発生する圧電電流が検出されて電気信号に増幅変化され、これがＰＬＬ回路６１へ出力される。ＰＬＬ回路６１では、振動片５３の共振周波数の変化量が検出され、その変化量を表す電気信号が生成され、生成された電気信号が制御部６２へ出力される。制御部６２は、前述した周波数の変化量が一定に保持されるように、試料スキャナ５１に制御信号が出力される。そして、試料スキャナ５１により探針２と試料８との間の距離が一定になるよう調整しつつ、試料８が探針２に対して２次元平面内で相対的に移動される。 A PLL (Phase Locked Loop) circuit 61 is connected to the detection electrode of the crystal resonator 52 via a preamplifier 60. In the preamplifier 60, the piezoelectric current generated by the vibration of the crystal resonator 52 is detected and amplified and changed into an electric signal, which is output to the PLL circuit 61. In the PLL circuit 61, the amount of change in the resonance frequency of the resonator element 53 is detected, an electric signal representing the amount of change is generated, and the generated electric signal is output to the control unit 62. The control unit 62 outputs a control signal to the sample scanner 51 so that the above-described frequency change amount is kept constant. Then, the sample 8 is moved relative to the probe 2 in a two-dimensional plane while adjusting the distance between the probe 2 and the sample 8 to be constant by the sample scanner 51.
　本実施例の近接場偏光顕微鏡１では、ＡＦＭ像と共に、試料８の微小領域における磁気ヒステリシスを測定できるのが好ましい。この場合、本実施例の近接場偏光顕微鏡１は、試料スキャナ５１の走査手段により設定量ずつ試料８を移動させ、その各点におけるｚ座標を記録する座標記録手段と、設定値間において外部磁界を変動させる磁界変動手段と、前記各点において外部磁界を変動させた際の情報を記憶する記憶手段とをさらに備える。試料スキャナ５１の走査手段を設定量ずつ移動させる場合には、パーソナルコンピュータから構成される端末装置と試料スキャナ５１とが接続され、端末装置にその設定量を設定しておけばよい。 In the near-field polarizing microscope 1 of the present embodiment, it is preferable that the magnetic hysteresis in the minute region of the sample 8 can be measured together with the AFM image. In this case, the near-field polarizing microscope 1 of this embodiment moves the sample 8 by a set amount by the scanning unit of the sample scanner 51 and records the z coordinate at each point, and an external magnetic field between the set values. And a storage means for storing information when the external magnetic field is changed at each of the points. When moving the scanning means of the sample scanner 51 by a set amount, a terminal device constituted by a personal computer and the sample scanner 51 are connected, and the set amount may be set in the terminal device.
　座標記録手段は、試料８の各点におけるｚ座標を記録する手段とされる。座標記録手段は、試料スキャナ５１と接続され、この試料スキャナ５１から送られるｚ座標の情報を記録することができる。ここで、ｚ座標は、試料８の起伏の高さ情報とされる。このｚ座標は、試料８のｘｙ座標（試料表面の場所）と対応づけて、座標記録手段に記録される。磁界変動手段は、磁界印加手段７に備えられており、前記端末装置に接続される。この端末装置に、変動させる磁界の値が設定される。本実施例では、たとえば、＋１テスラから－１テスラへ、そして－１テスラから＋１テスラへ連続的に変動するように設定される。記憶手段は、検出装置１７と接続され、前記各点において、外部磁界変動手段により磁界を変動させた際の情報を記憶することができる。 The coordinate recording means is means for recording the z coordinate at each point of the sample 8. The coordinate recording means is connected to the sample scanner 51 and can record the information of the z coordinate sent from the sample scanner 51. Here, the z coordinate is the height information of the undulation of the sample 8. The z coordinate is recorded in the coordinate recording means in association with the xy coordinate (location on the sample surface) of the sample 8. The magnetic field changing means is provided in the magnetic field applying means 7 and connected to the terminal device. In this terminal device, the value of the magnetic field to be changed is set. In this embodiment, for example, it is set so as to continuously vary from +1 Tesla to -1 Tesla and from -1 Tesla to +1 Tesla. The storage means is connected to the detection device 17 and can store information when the magnetic field is changed by the external magnetic field changing means at each point.
　従って、取得したｚ座標の情報を２次元的に表示することでＡＦＭ像を得ることができる。また、これに加えて、ｚ軸に磁場軸（または磁界軸）をとりｘｙ軸に試料の表面の場所を表すような３次元の磁気ヒステリシスデータを２つ得ることができる。このようにして、各点ごとの磁気ヒステリシスとＡＦＭ像とを同期して取得することができる。ここで、２つとは、－１テスラから＋１テスラへ磁界を変動させた際のものと、＋１テスラから－１テスラへ磁界を変動させた際のものであり、往復の１セットのことである。 Therefore, an AFM image can be obtained by two-dimensionally displaying the acquired z coordinate information. In addition to this, two three-dimensional magnetic hysteresis data can be obtained in which the magnetic field axis (or magnetic field axis) is taken as the z axis and the surface location of the sample is shown as the xy axis. In this way, the magnetic hysteresis and the AFM image for each point can be acquired in synchronization. Here, the two are a case where the magnetic field is changed from -1 Tesla to +1 Tesla and a case where the magnetic field is changed from +1 Tesla to -1 Tesla, which is one set of reciprocation. .
　データ取得後、特定の磁場軸でスライスすることで、たとえば、ゼロ磁界から増加させた際の０．５テスラ時の磁気像（２次元）を、ＡＦＭ像と共に得ることができる。また、特定の場所の磁気ヒステリシスを確認する際には、その箇所の磁気ヒステリシス曲線を抜き出せばよい。 After data acquisition, by slicing along a specific magnetic field axis, for example, a magnetic image (two-dimensional) at 0.5 Tesla when increasing from zero magnetic field can be obtained together with an AFM image. Further, when confirming the magnetic hysteresis at a specific location, the magnetic hysteresis curve at that location may be extracted.
　本実施例の近接場偏光顕微鏡１によれば、上部磁極４３と下部磁極４４との間に配置されるカンチレバー３が非磁性材料から形成されることで、そのカンチレバー３は、磁界印加手段７により印加される磁界の影響を受けることがない。従って、外部から磁界を印加しつつ、試料８の磁区を正確に検出することができる。これに加えて、本実施例の近接場偏光顕微鏡１によれば、上部磁極４３と下部磁極４４との間に配置される試料支持片４９、試料ホルダ５７、探針ホルダ５６および探針支持片４７も非磁性材料から形成されることで、それらも磁界の影響を受けることがない。 According to the near-field polarization microscope 1 of the present embodiment, the cantilever 3 disposed between the upper magnetic pole 43 and the lower magnetic pole 44 is formed of a nonmagnetic material. It is not affected by the applied magnetic field. Therefore, the magnetic domain of the sample 8 can be accurately detected while applying a magnetic field from the outside. In addition to this, according to the near-field polarization microscope 1 of the present embodiment, the sample support piece 49, the sample holder 57, the probe holder 56, and the probe support piece arranged between the upper magnetic pole 43 and the lower magnetic pole 44. Since 47 is formed of a nonmagnetic material, they are not affected by the magnetic field.
　また、本実施例の近接場偏光顕微鏡１によれば、カンチレバー３、試料支持片４９、試料ホルダ５７、探針ホルダ５６および探針支持片４７が非導電性材料から形成されることで、渦電流による影響を抑制することができる。このようにして、カンチレバー３、試料支持片４９、試料ホルダ５７、探針ホルダ５６および探針支持片４７が非磁性材料かつ非導電性材料から形成されることで、磁界の吸引力だけでなく、磁界変動による影響をなくすことができる。また、本実施例の近接場偏光顕微鏡１によれば、上部磁極４３と下部磁極４４との間に基体３２の外周面から試料支持片４９および探針支持片４７を差し込む構成とすることで、上部磁極４３と下部磁極４４との間隔を小さくして磁界をより強くすることができる。また、本実施例の近接場偏光顕微鏡１によれば、磁界を印加しつつ、近接場光を用いて試料８の磁区が検出できるため、微小領域での磁性ドットの磁化の変化を観察することができる。さらに、本実施例の近接場偏光顕微鏡１によれば、下部磁極４４の上端部が先細りに形成されることで、上部磁極４３と下部磁極４４との間隔を小さくして磁界をより強くすることができる。 Further, according to the near-field polarization microscope 1 of the present embodiment, the cantilever 3, the sample support piece 49, the sample holder 57, the probe holder 56, and the probe support piece 47 are formed of a nonconductive material, so that the vortex The influence of current can be suppressed. In this manner, the cantilever 3, the sample support piece 49, the sample holder 57, the probe holder 56, and the probe support piece 47 are formed of the nonmagnetic material and the nonconductive material, so that not only the magnetic field attractive force is obtained. , The influence of the magnetic field fluctuation can be eliminated. Further, according to the near-field polarization microscope 1 of the present embodiment, the sample support piece 49 and the probe support piece 47 are inserted from the outer peripheral surface of the base 32 between the upper magnetic pole 43 and the lower magnetic pole 44. The distance between the upper magnetic pole 43 and the lower magnetic pole 44 can be reduced to make the magnetic field stronger. Further, according to the near-field polarizing microscope 1 of the present embodiment, the magnetic domain of the sample 8 can be detected using the near-field light while applying a magnetic field, so that the change in the magnetization of the magnetic dot in the minute region can be observed. Can do. Furthermore, according to the near-field polarization microscope 1 of the present embodiment, the upper end portion of the lower magnetic pole 44 is formed to be tapered, so that the distance between the upper magnetic pole 43 and the lower magnetic pole 44 is reduced and the magnetic field is made stronger. Can do.
　本発明の近接場偏光顕微鏡は、前記実施例の構成に限らず、適宜変更可能である。たとえば、磁界印加手段７は、前記実施例の構成に限定されるものではない。図３および図４は、図１の近接場偏光顕微鏡の変形例を示す図であり、図３は、磁界印加手段の概略側面図、図４は、磁界印加手段の概略平面図であり、カンチレバーと試料とが配置された状態を示している。 The near-field polarizing microscope of the present invention is not limited to the configuration of the above-described embodiment, and can be changed as appropriate. For example, the magnetic field applying unit 7 is not limited to the configuration of the above embodiment. 3 and 4 are views showing a modification of the near-field polarization microscope of FIG. 1, FIG. 3 is a schematic side view of the magnetic field applying means, and FIG. 4 is a schematic plan view of the magnetic field applying means. And a sample are arranged.
　本変形例の磁界印加手段７は、上下に離隔して配置される上部リターンヨーク７０および下部リターンヨーク７１と、上部リターンヨーク７０と下部リターンヨーク７１とを接続する鉄心７２と、鉄心７２に設けられるコイル７３と、下部リターンヨーク７１に設けられる柱体７４とを備える。上部リターンヨーク７０と下部リターンヨーク７１とは、一端部同士が円柱状の鉄心７２により接続され、この鉄心７２にコイル７３が設けられる。柱体７４は、円柱状に形成され、下部リターンヨーク７１の他端部に立設される。この際、上部リターンヨーク７０の他端部と柱体７４の上端部とが隙間を空けた状態で互いに対応するように配置される。柱体７４の上端部は、上方へ行くに従って先細りとなる円錐台状に形成される。これにより、上部リターンヨーク７０が上部磁極４３とされる一方、柱体７４が下部磁極４４とされる。なお、鉄心７２は、円柱状に限定されるものではなく、たとえば、スペース効率上、四角柱状に形成してもよい。 The magnetic field applying means 7 of this modification is provided on the iron core 72, an upper return yoke 70 and a lower return yoke 71 that are spaced apart from each other, an iron core 72 that connects the upper return yoke 70 and the lower return yoke 71, and And a column body 74 provided on the lower return yoke 71. One end of the upper return yoke 70 and the lower return yoke 71 are connected by a cylindrical iron core 72, and a coil 73 is provided on the iron core 72. The column 74 is formed in a columnar shape and is erected on the other end of the lower return yoke 71. At this time, the other end of the upper return yoke 70 and the upper end of the column 74 are disposed so as to correspond to each other with a gap left therebetween. The upper end of the column 74 is formed in a truncated cone shape that tapers as it goes upward. Thus, the upper return yoke 70 is the upper magnetic pole 43, and the column body 74 is the lower magnetic pole 44. In addition, the iron core 72 is not limited to a columnar shape, and may be formed in a rectangular column shape, for example, in terms of space efficiency.
　カンチレバー３および試料８は、上部磁極４３となる上部リターンヨーク７０と下部磁極４４となる柱体７４の間の隙間に配置される。この状態において、コイル７３に電流を流すことで、上部リターンヨーク７０と柱体７４とがそれぞれ上部磁極４３と下部磁極４４となり、磁界を発生させることができ、試料８に磁界を印加することができる。本変形例では、細長い板状の探針支持片４７および試料支持片４９は必要としないが、その他のカンチレバー３やホルダ５６，５７などは非磁性材料から形成されることで、磁界の影響を受けることがない。それに加えて、それらが非導電性材料から形成されることで、渦電流による影響を抑制することができる。すなわち、非磁性材料かつ非導電性材料から形成されることで、磁界の吸引力だけでなく磁界変動による影響をなくすことができる。また、本変形例の磁界印加手段７では、近接場偏光顕微鏡１全体をコンパクトにすることができる。さらに、本変形例の磁界印加手段７を用いた近接場偏光顕微鏡１は、既存の原子間力顕微鏡の構成を適用し易い。 The cantilever 3 and the sample 8 are disposed in a gap between the upper return yoke 70 that becomes the upper magnetic pole 43 and the column body 74 that becomes the lower magnetic pole 44. In this state, when an electric current is passed through the coil 73, the upper return yoke 70 and the column 74 become the upper magnetic pole 43 and the lower magnetic pole 44, respectively, and a magnetic field can be generated and the magnetic field can be applied to the sample 8. it can. In this modification, the elongated plate-like probe support piece 47 and the sample support piece 49 are not required, but the other cantilevers 3, the holders 56 and 57, etc. are made of a nonmagnetic material, so that the influence of the magnetic field is reduced. I do not receive it. In addition, the influence of eddy currents can be suppressed by forming them from a non-conductive material. That is, by being formed from a nonmagnetic material and a nonconductive material, it is possible to eliminate not only the attractive force of the magnetic field but also the influence of the magnetic field fluctuation. Moreover, in the magnetic field application means 7 of this modification, the whole near-field polarizing microscope 1 can be made compact. Furthermore, the near-field polarizing microscope 1 using the magnetic field applying means 7 of this modification can easily apply the configuration of an existing atomic force microscope.
　また、前記実施例では、水晶振動子５２によりカンチレバー３を振動させたが、励振ピエゾ５５によりカンチレバー３を振動させてもよい。図５は、図１の近接場偏光顕微鏡の別の変形例を示す概略構成図であり、一部を省略して示している。本変形例の近接場偏光顕微鏡１は、基本的には前記実施例と同様の構成である。そこで、以下においては、両者の異なる点を中心に説明し、対応する箇所には同一の符号を付して説明する。 In the above-described embodiment, the cantilever 3 is vibrated by the crystal resonator 52, but the cantilever 3 may be vibrated by the excitation piezo 55. FIG. 5 is a schematic configuration diagram showing another modified example of the near-field polarization microscope of FIG. 1, and a part thereof is omitted. The near-field polarizing microscope 1 of this modification example has basically the same configuration as that of the above embodiment. Therefore, in the following description, differences between the two will be mainly described, and corresponding portions will be described with the same reference numerals.
　図５に示されるように、カンチレバー３は、励振ピエゾ５５に直接設けられる。この励振ピエゾ５５は、前述した探針ホルダ５６に設けられ、この探針ホルダ５６は前述した探針支持片４７に設けられる。励振ピエゾ５５は、図示しない出力装置からのカンチレバー３の共振周波数で励振される。従って、励振ピエゾ５５の振動がカンチレバー３に伝達されて、カンチレバー３が振動される。本変形例の近接場偏光顕微鏡１は、カンチレバー３の変位を検出する変位検出光学系６３と、ダイクロイックミラー６４とをさらに備える。変位検出光学系６３は、変位検出レーザ光６５の変位レーザ光源６６と、光によってカンチレバー３の変位が検出される変位検出装置６７と、レンズ６８とを有して構成される。なお、本変形例では、膜１０は、梁部９の一端部を残して、梁部９の表面にも探針２の内面から連続して形成される。膜１０は、梁部９にその一端部を残して形成されることに限定されるものではなく、梁部９の表面全体に形成してもよい。 As shown in FIG. 5, the cantilever 3 is directly provided on the excitation piezo 55. The excitation piezo 55 is provided on the probe holder 56 described above, and the probe holder 56 is provided on the probe support piece 47 described above. The excitation piezo 55 is excited at the resonance frequency of the cantilever 3 from an output device (not shown). Accordingly, the vibration of the excitation piezo 55 is transmitted to the cantilever 3 and the cantilever 3 is vibrated. The near-field polarization microscope 1 of this modification further includes a displacement detection optical system 63 that detects the displacement of the cantilever 3 and a dichroic mirror 64. The displacement detection optical system 63 includes a displacement laser light source 66 for the displacement detection laser light 65, a displacement detection device 67 for detecting the displacement of the cantilever 3 by the light, and a lens 68. In this modification, the film 10 is continuously formed on the surface of the beam portion 9 from the inner surface of the probe 2 except for one end portion of the beam portion 9. The film 10 is not limited to be formed by leaving one end portion of the beam portion 9, and may be formed on the entire surface of the beam portion 9.
　変位検出装置６７は、本変形例では４分割フォトダイオードとされ、カンチレバー３からの変位検出レーザ光６５の戻り光により、カンチレバー３の変位を検出することができる。なお、本実施例では、変位検出レーザ光６５は、たとえば、５３２ｎｍの緑の波長とされる。このような変位検出光学系６３、観察照明光学系５および磁区検出光学系４とに対して、対物レンズ６は共通とされる。これにより、構成の簡素化、占有空間の小型化および組立精度の向上を図ることができる。ダイクロイックミラー６４は、変位検出レーザ光６５の波長光、本実施例では５３２ｎｍの緑の光を反射させることができる。この際、緑の光の一部は、ダイクロイックミラー６４を通過する。このようにして光強度が減衰されつつ透過された緑の光によって、眩しさが和らげられたビームスポットを視認することができ、これにより、緑のビーム位置をカメラでモニタすることができる。また、ダイクロイックミラー６４は、変位検出レーザ光６５の波長以外の波長光が透過され、照明光２９を変位検出レーザ光６５と共に対物レンズ６へ向かわせる波長選択性を有する。 The displacement detector 67 is a four-division photodiode in this modification, and can detect the displacement of the cantilever 3 by the return light of the displacement detection laser beam 65 from the cantilever 3. In this embodiment, the displacement detection laser beam 65 has a green wavelength of 532 nm, for example. The objective lens 6 is common to the displacement detection optical system 63, the observation illumination optical system 5, and the magnetic domain detection optical system 4. Thereby, simplification of a structure, size reduction of an occupation space, and the improvement of an assembly precision can be aimed at. The dichroic mirror 64 can reflect the wavelength light of the displacement detection laser beam 65, which is green light of 532 nm in this embodiment. At this time, part of the green light passes through the dichroic mirror 64. In this way, it is possible to visually recognize the beam spot whose glare has been reduced by the transmitted green light while the light intensity is attenuated, and the position of the green beam can be monitored by the camera. Further, the dichroic mirror 64 has wavelength selectivity that allows light having a wavelength other than the wavelength of the displacement detection laser light 65 to pass therethrough and directs the illumination light 29 together with the displacement detection laser light 65 toward the objective lens 6.
　本変形例の近接場偏光顕微鏡１は、前記実施例の近接場偏光顕微鏡１と同様にして、試料８の磁区が検出される。この際、変位レーザ光源６６からの変位検出レーザ光６５は、ダイクロイックミラー６４にて反射され、ダイクロイックミラー４６を透過して対物レンズ６を通過し、カンチレバー３の膜１０で反射される。この戻り光は、レンズ６８を介して変位検出装置６７に導入される。戻り光は、カンチレバー３の撓曲、すなわち変位に応じて、変位検出装置６７への入射角変化（すなわちスポット位置変化）、あるいは位置が変化することから、変位検出装置６７における光電変換の各部の入射光量の変化が生じる。従って、これらによる出力の演算により、カンチレバー３の撓みの検出、ひいては原子間力を検出することができる。 In the near-field polarizing microscope 1 of this modification, the magnetic domain of the sample 8 is detected in the same manner as the near-field polarizing microscope 1 of the above embodiment. At this time, the displacement detection laser light 65 from the displacement laser light source 66 is reflected by the dichroic mirror 64, passes through the dichroic mirror 46, passes through the objective lens 6, and is reflected by the film 10 of the cantilever 3. This return light is introduced into the displacement detection device 67 via the lens 68. The return light changes in the incident angle to the displacement detection device 67 (that is, change in spot position) or the position according to the bending of the cantilever 3, that is, the displacement. A change in the amount of incident light occurs. Therefore, by calculating the output from these, it is possible to detect the deflection of the cantilever 3 and thus the atomic force.
　原子間力を検出した信号が制御装置６９に入力され、制御装置６９から試料スキャナ５１へ制御信号が出力される。そして、試料スキャナ５１により試料ステージ５０のｚ軸方向の調整がなされる。このようにして、原子間力が一定となるようにフィードバック制御することで、常時、探針２と試料８との間隔を一定に保持することができる。言い換えれば、近接場光は、常時、試料８の表面に一定条件で照射される。 A signal that detects the atomic force is input to the control device 69, and a control signal is output from the control device 69 to the sample scanner 51. Then, the sample scanner 51 adjusts the sample stage 50 in the z-axis direction. Thus, by performing feedback control so that the atomic force is constant, the distance between the probe 2 and the sample 8 can always be kept constant. In other words, the near-field light is always applied to the surface of the sample 8 under a certain condition.
　また、前記実施例では、磁区検出光学系４においてλ／４板１５が設けられたが、これを用いないこともできる。この場合、磁区検出レーザ光１１は、λ／２板１４により入射された直線偏光が回転され、ダイクロイックミラー１６へ進む。また、λ／４板１５およびλ／４板２１を用いない構成とすることもできる。なお、λ／２板１４は、前述したように直線偏光を回転させるだけのものなので、設けなくてもよい。 In the above embodiment, the λ / 4 plate 15 is provided in the magnetic domain detection optical system 4, but this may not be used. In this case, the linearly polarized light incident on the magnetic domain detection laser beam 11 by the λ / 2 plate 14 is rotated and proceeds to the dichroic mirror 16. In addition, the λ / 4 plate 15 and the λ / 4 plate 21 may not be used. Note that the λ / 2 plate 14 need not be provided because it merely rotates linearly polarized light as described above.
　また、前記実施例では、探針支持片４７と試料支持片４９とが基体３２の径方向に互いに対向するように配置されたが、これに限定されるものではなく、探針支持片４７と試料支持片４９とが互いに直交するよう配置してもよい。また、前記実施例では、検出装置１７が光電子増倍管とされたが、分光器としてもよい。この場合、狭帯域干渉フィルタ１８は用いられず、ダイクロイックミラー１６およびダイクロイックミラー４６がハーフミラーであるビームスプリッタとされる。また、不要光排除手段２２とλ／４板２１との間、またはＧ－Ｔアナライザ２０とレンズ１９との間にビームスプリッタが配置され、戻り光を、光電子増倍管へ向かう光とビームスプリッタで反射される光とに分岐させてもよい。この場合、ビームスプリッタで反射された光は分光器へ導入され、光電子増倍管での検出信号と分光器での検出信号とを同時に取得することができる。 In the above-described embodiment, the probe support piece 47 and the sample support piece 49 are arranged so as to face each other in the radial direction of the base 32. However, the present invention is not limited to this, and the probe support piece 47 and You may arrange | position so that the sample support piece 49 may mutually orthogonally cross. Moreover, in the said Example, although the detection apparatus 17 was used as the photomultiplier tube, it is good also as a spectrometer. In this case, the narrowband interference filter 18 is not used, and the dichroic mirror 16 and the dichroic mirror 46 are beam splitters that are half mirrors. In addition, a beam splitter is disposed between the unnecessary light eliminating means 22 and the λ / 4 plate 21 or between the GT analyzer 20 and the lens 19, and the return light is converted into light directed to the photomultiplier tube and the beam splitter. The light may be branched to the light reflected by. In this case, the light reflected by the beam splitter is introduced into the spectrometer, and the detection signal from the photomultiplier tube and the detection signal from the spectrometer can be acquired simultaneously.
　また、前記実施例では、水晶振動子５２の振動片５３の周波数がＰＬＬ回路６１により検出され、これに基づいて探針２と試料８との距離が一定に保持されたが、これに限定されるものではなく、たとえば、前述した変位検出光学系６３を用いてもよい。さらに、前記変形例では、励振ピエゾ５５の振動によるカンチレバー３の振動が変位検出光学系６３にて検出されたが、これに限定されるものではなく、たとえば、励振ピエゾ５５の周波数がＰＬＬ回路６１にて検出される構成としてもよい。なお、ＰＬＬ回路６１は、試料８表面をカンチレバー３で触れながらなぞりつつ、カンチレバー３の動きで試料８表面の凹凸を検出するコンタクト方式や、カンチレバー３を共振周波数で強制励振させて試料８表面をなぞるタッピング方式にも対応させている。 In the above-described embodiment, the frequency of the resonator element 53 of the crystal resonator 52 is detected by the PLL circuit 61. Based on this, the distance between the probe 2 and the sample 8 is kept constant. For example, the above-described displacement detection optical system 63 may be used. Further, in the modification, the vibration of the cantilever 3 due to the vibration of the excitation piezo 55 is detected by the displacement detection optical system 63. However, the present invention is not limited to this. For example, the frequency of the excitation piezo 55 is the PLL circuit 61. It is good also as a structure detected by. The PLL circuit 61 is configured to contact the surface of the sample 8 while touching the surface of the sample 8 with the cantilever 3 while detecting the irregularities on the surface of the sample 8 by the movement of the cantilever 3, or by forcibly exciting the cantilever 3 at the resonance frequency. It also supports the tapping method.
　図６は、図１の近接場偏光顕微鏡の他の変形例を示す概略構成図であり、一部を省略して示している。本変形例の近接場偏光顕微鏡１は、基本的には前記実施例と同様の構成である。そこで、以下においては、両者の異なる点を中心に説明し、対応する箇所には同一の符号を付して説明する。 FIG. 6 is a schematic configuration diagram showing another modified example of the near-field polarization microscope of FIG. 1, and a part thereof is omitted. The near-field polarizing microscope 1 of this modification example has basically the same configuration as that of the above embodiment. Therefore, in the following description, differences between the two will be mainly described, and corresponding portions will be described with the same reference numerals.
　図６に示されるように、消光可能なポラライザが二つ設けられる。本変形例では、両ポラライザがＧ－Ｔアナライザとされる。具体的には、図６に示されるように、試料８や探針２などからの戻り光の進行方向において、前述した不要光排除手段２２よりも下流側に配置される第一Ｇ－Ｔアナライザ７０と、前記進行方向において第一Ｇ－Ｔアナライザ７０よりも下流側で、かつ、前記進行方向においてレンズ１９よりも上流側に配置される第二Ｇ－Ｔアナライザ７１とが設けられる。第一Ｇ－Ｔアナライザ７０と第二Ｇ－Ｔアナライザ７１とは、前述したＧ－Ｔアナライザ２０と同様のものである。すなわち、第一Ｇ－Ｔアナライザ７０および第二Ｇ－Ｔアナライザ７１は、試料８で反射された近接場光とそれ以外の光とを含む光から、前記それ以外の光を消光させて、試料で反射された近接場光とそれ以外の光とを分離し近接場光のみの偏向状態を解析することができるものである。なお、本変形例では、前記実施例のλ／４板１５，２１が設けられていないが、これに限定されるものではなく、λ／４板１５，２１が設けられていてもよい。その他の構成は、前記実施例と同様のため、説明は省略する。 As shown in FIG. 6, two polarizers that can be quenched are provided. In this modification, both polarizers are GT analyzers. Specifically, as shown in FIG. 6, in the traveling direction of the return light from the sample 8, the probe 2, etc., the first GT analyzer disposed on the downstream side of the unnecessary light eliminating means 22 described above. 70 and a second GT analyzer 71 disposed downstream of the first GT analyzer 70 in the traveling direction and upstream of the lens 19 in the traveling direction. The first GT analyzer 70 and the second GT analyzer 71 are the same as the GT analyzer 20 described above. That is, the first GT analyzer 70 and the second GT analyzer 71 extinguish the other light from the light including the near-field light reflected by the sample 8 and the other light, so that the sample It is possible to separate the near-field light reflected by and the other light and analyze the deflection state of only the near-field light. In this modification, the λ / 4 plates 15 and 21 of the above embodiment are not provided. However, the present invention is not limited to this, and the λ / 4 plates 15 and 21 may be provided. Since other configurations are the same as those in the above-described embodiment, description thereof is omitted.
　このような構成により、本変形例では、試料８からの戻り光と探針２の内面で反射された不要のファーフィールド光の戻り光とを含む反射光が第一Ｇ－Ｔアナライザ７０に導入される。そして、第一Ｇ－Ｔアナライザ７０により、前記反射光から探針２で反射されたファーフィールド光の戻り光を除去して、試料８からの反射近接場光を抽出することができる。なお、第一Ｇ－Ｔアナライザ７０では、前記反射光から探針２で反射されたファーフィールド光の戻り光を完全に除去することはできず、抽出された光には、探針２で反射されたファーフィールド光の戻り光が含まれている。 With such a configuration, in this modification, reflected light including the return light from the sample 8 and the return light of unnecessary far-field light reflected by the inner surface of the probe 2 is introduced into the first GT analyzer 70. Is done. Then, the first GT analyzer 70 can extract the reflected near-field light from the sample 8 by removing the return light of the far-field light reflected by the probe 2 from the reflected light. In the first GT analyzer 70, the return light of the far field light reflected by the probe 2 cannot be completely removed from the reflected light, and the extracted light is reflected by the probe 2. The far field light returned light is included.
　そして、第一Ｇ－Ｔアナライザ７０を通過した前記反射光は、第二Ｇ－Ｔアナライザ７１に導入される。第二Ｇ－Ｔアナライザ７１の偏光角を調整しておくことで、第一Ｇ－Ｔアナライザ７０を通過した前記反射光から、第一Ｇ－Ｔアナライザ７０で除去できなかったファーフィールド光の戻り光を除去して、試料８からの戻り光を抽出することができる。このようにして、直線偏光の場合、第一Ｇ－Ｔアナライザ７０と第二Ｇ－Ｔアナライザ７１とを設けることで、試料８で反射された近接場光とそれ以外の光とをより確実に分けることができ、計測対象である前記近接場光をより確実に抽出することができる。すなわち、第一Ｇ－Ｔアナライザ７０にて回折光を消光させて近接場光と分離させることができ、第二Ｇ－Ｔアナライザ７１にて近接場光の偏向について解析することができる。 Then, the reflected light that has passed through the first GT analyzer 70 is introduced into the second GT analyzer 71. By adjusting the polarization angle of the second GT analyzer 71, the return of far-field light that cannot be removed by the first GT analyzer 70 from the reflected light that has passed through the first GT analyzer 70. The return light from the sample 8 can be extracted by removing the light. In this way, in the case of linearly polarized light, by providing the first GT analyzer 70 and the second GT analyzer 71, the near-field light reflected by the sample 8 and the other light can be more reliably obtained. The near-field light that is the measurement target can be extracted more reliably. That is, the first GT analyzer 70 can quench the diffracted light and separate it from the near-field light, and the second GT analyzer 71 can analyze the deflection of the near-field light.
　なお、第一Ｇ－Ｔアナライザ７０および第二Ｇ－Ｔアナライザ７１は、試料８の磁区検出前に調整がなされている。具体的には、第一Ｇ－Ｔアナライザ７０および第二Ｇ－Ｔアナライザ７１は、試料８の磁区検出時よりも探針２が試料８から離された状態（探針２を試料８表面から原子間力が無視できる程度に小さくなる位置まで離した状態）において、検出装置１７で検出される光が最小となるように調整されている。本変形例では、探針２が試料８から２０ｎｍ以上離されて、探針２と試料８との間の原子間力が小さい状態で、検出装置１７で検出される光がほぼゼロあるいは最小値になるように、第一Ｇ－Ｔアナライザ７０および第二Ｇ－Ｔアナライザ７１が回転されて調整されている。この調整後に、探針２が試料８に接触されたコンタクト状態、または探針２と試料８との間に形成される隙間が維持されたノンコンタクト状態とされて原子間力が一定に制御され、第二Ｇ－Ｔアナライザ７１が回転されて検出装置１７で検出される光強度が最小値と最大値との間となるように設定される。すなわち、検出装置１７で検出される光強度が最小値と最大値との間となるように、第二Ｇ－Ｔアナライザが回転されて調整される。本変形例では、検出装置１７で検出される光がほぼゼロとなるように調整された状態から、第二Ｇ－Ｔアナライザ７１を約４５度回転させることで、検出装置１７で検出される光強度が最小値と最大値との間となるように設定される。このようにして、第二Ｇ－Ｔアナライザ７１の偏光角が調整される。そして、第二Ｇ－Ｔアナライザ７１の偏光角が調整された状態で、試料８の磁区検出が行われる。以上のようにして、探針２の内面で反射された不要のファーフィールド光の戻り光が排除され、このようにして導かれた光のみが、直接、あるいはレンズ１９と狭帯域干渉フィルタ１８とを介して検出装置１７へ導入され、電気信号に変換した出力を取り出すことができる。すなわち、ノイズが除去された試料８の磁区を検出することができる。 The first GT analyzer 70 and the second GT analyzer 71 are adjusted before the magnetic domain of the sample 8 is detected. Specifically, in the first GT analyzer 70 and the second GT analyzer 71, the probe 2 is more distant from the sample 8 than when the magnetic domain of the sample 8 is detected (the probe 2 is separated from the surface of the sample 8). In a state where the atomic force is separated to a level where it can be ignored, the light detected by the detection device 17 is adjusted to be minimum. In this modification, the light detected by the detection device 17 is almost zero or the minimum value when the probe 2 is separated from the sample 8 by 20 nm or more and the atomic force between the probe 2 and the sample 8 is small. Thus, the first GT analyzer 70 and the second GT analyzer 71 are rotated and adjusted. After this adjustment, the atomic force is controlled to be constant by setting the probe 2 in contact with the sample 8 or in the non-contact state in which the gap formed between the probe 2 and the sample 8 is maintained. The light intensity detected by the detection device 17 by rotating the second GT analyzer 71 is set to be between the minimum value and the maximum value. That is, the second GT analyzer is rotated and adjusted so that the light intensity detected by the detection device 17 is between the minimum value and the maximum value. In this modification, the light detected by the detection device 17 is rotated by rotating the second GT analyzer 71 about 45 degrees from the state where the light detected by the detection device 17 is adjusted to be substantially zero. The intensity is set to be between the minimum value and the maximum value. In this way, the polarization angle of the second GT analyzer 71 is adjusted. Then, the magnetic domain detection of the sample 8 is performed with the polarization angle of the second GT analyzer 71 adjusted. As described above, the return light of unnecessary far-field light reflected on the inner surface of the probe 2 is eliminated, and only the light guided in this way is directly or the lens 19 and the narrowband interference filter 18. The output converted into an electrical signal can be taken out to the detection device 17 via. That is, the magnetic domain of the sample 8 from which noise has been removed can be detected.
　図７は、図１の近接場偏光顕微鏡のさらに別の変形例を示す概略構成図であり、一部を省略して示している。本変形例の近接場偏光顕微鏡１は、基本的には前記実施例と同様の構成である。そこで、以下においては、両者の異なる点を中心に説明し、対応する箇所には同一の符号を付して説明する。 FIG. 7 is a schematic configuration diagram showing still another modified example of the near-field polarization microscope of FIG. 1, and a part thereof is omitted. The near-field polarizing microscope 1 of this modification example has basically the same configuration as that of the above embodiment. Therefore, in the following description, differences between the two will be mainly described, and corresponding portions will be described with the same reference numerals.
　本変形例では、磁区検出光学系４は、レーザ光源１２と、絞り１３と、λ／２板１４と、ダイクロイックミラー１６と、不要光排除手段２２と、狭帯域干渉フィルタ１８と、偏光ビームスプリッタ７２と、二つの検出装置７３，７４と、差動アンプ７５と、加算アンプ７６と、除算アンプ７７と、画像検出部７８とを備える。その他の構成は、前記実施例と同様のため、説明は省略する。 In this modification, the magnetic domain detection optical system 4 includes a laser light source 12, a diaphragm 13, a λ / 2 plate 14, a dichroic mirror 16, an unnecessary light exclusion unit 22, a narrowband interference filter 18, a polarization beam splitter. 72, two detection devices 73 and 74, a differential amplifier 75, an addition amplifier 76, a division amplifier 77, and an image detection unit 78. Since other configurations are the same as those in the above-described embodiment, description thereof is omitted.
　図７に示されるように、試料８や探針２などからの戻り光の進行方向において、上流側から順に、不要光排除手段２２、狭帯域干渉フィルタ１８、偏光ビームスプリッタ７２が配置される。偏光ビームスプリッタ７２は、試料８からの戻り光と探針２の内面で反射された不要のファーフィールド光の戻り光とを含む反射光を、二つの方向の直線偏光成分に分離するものである。検出装置７３，７４は、導入される試料８からの戻り光の態様、目的とする検出信号態様などに応じて、たとえば、フォトダイオード、光電子増倍管（フォトマルチプライヤ）、分光器などによって構成される。検出装置７３は、偏光ビームスプリッタ７２で二つに分離された直線偏光成分の内の一方の直線偏光成分が導入されるものであり、検出装置７４は、偏光ビームスプリッタ７２で二つに分離された直線偏光成分の内の他方の直線偏光成分が導入されるものである。差動アンプ７５および加算アンプ７６は、検出装置７３および検出装置７４に接続されている。除算アンプ７７は、差動アンプ７５および加算アンプ７６に接続されている。画像検出部７８は、除算アンプ７７に接続されている。なお、本変形例では、偏光ビームスプリッタ７２に入射する偏光面が約４５度となるように調整されている。 As shown in FIG. 7, in the traveling direction of the return light from the sample 8, the probe 2, etc., the unnecessary light eliminating means 22, the narrow band interference filter 18, and the polarization beam splitter 72 are arranged in order from the upstream side. The polarization beam splitter 72 separates the reflected light including the return light from the sample 8 and the return light of unnecessary far-field light reflected by the inner surface of the probe 2 into linearly polarized components in two directions. . The detection devices 73 and 74 are configured by, for example, a photodiode, a photomultiplier tube (photomultiplier), a spectroscope, or the like according to the mode of return light from the sample 8 to be introduced and the target detection signal mode. Is done. The detecting device 73 is one in which one of the linearly polarized components separated by the polarizing beam splitter 72 is introduced, and the detecting device 74 is separated into two by the polarizing beam splitter 72. Of the linearly polarized light components, the other linearly polarized light component is introduced. The differential amplifier 75 and the addition amplifier 76 are connected to the detection device 73 and the detection device 74. The division amplifier 77 is connected to the differential amplifier 75 and the addition amplifier 76. The image detection unit 78 is connected to the division amplifier 77. In this modification, the polarization plane incident on the polarization beam splitter 72 is adjusted to be about 45 degrees.
　このような構成により、本変形例では、偏光ビームスプリッタ７２にて試料８で反射された近接場光とそれ以外の光とを含む光が二つの方向の直線偏光成分に分離され、一方の直線偏光成分が検出装置７３に導入されると共に、他方の直線偏光成分が検出装置７４に導入され、両検出装置７３，７４にて電気信号に変換された出力が差動アンプ７５および加算アンプ７６に導入される。差動アンプ７５により、検出装置７３からの出力と検出装置７４からの出力との差分が求められる。また、加算アンプ７６により、検出装置７３からの出力と検出装置７４からの出力との和分が求められる。前記差分に応じた出力が差動アンプ７５から除算アンプ７７に導入され、前記和分に応じた出力が加算アンプ７６から除算アンプ７７に導入され、除算アンプ７７により、前記差分が前記和分で割られる。すなわち、除算アンプ７７により、前記差分／前記和分が求められる。そして、前記差分／前記和分に応じた出力が画像検出部７８に導入され、画像検出部７８により偏向回転角の像が形成される。 With this configuration, in this modification, the light including the near-field light reflected by the sample 8 by the polarization beam splitter 72 and the other light is separated into linearly polarized light components in two directions. The polarization component is introduced into the detection device 73 and the other linear polarization component is introduced into the detection device 74, and the output converted into an electric signal by both the detection devices 73 and 74 is sent to the differential amplifier 75 and the addition amplifier 76. be introduced. The difference between the output from the detection device 73 and the output from the detection device 74 is obtained by the differential amplifier 75. The summing amplifier 76 obtains the sum of the output from the detection device 73 and the output from the detection device 74. An output corresponding to the difference is introduced from the differential amplifier 75 to the division amplifier 77, and an output corresponding to the sum is introduced from the addition amplifier 76 to the division amplifier 77. The division amplifier 77 causes the difference to be the sum. Cracked. That is, the difference / the sum is obtained by the division amplifier 77. Then, an output corresponding to the difference / the sum is introduced into the image detection unit 78, and an image with a deflection rotation angle is formed by the image detection unit 78.
　従って、本変形例によれば、前記反射光が二方向の直線偏光成分に分離されてそれぞれ検出され、両直線偏光成分の光強度の差分が両直線偏光成分の光強度の和分で割られて規格化されることで、入射光源の減少などの光強度変化の影響を抑制することができる。これにより、偏向変化分だけが抽出および補正されて、磁気カー効果のみを測定することができる。すなわち、本変形例によれば、バックグラウンドノイズを差し引くことができ、計測対象である近接場光の情報をより確実に抽出することができる。なお、本変形例において、狭帯域干渉フィルタ１８よりも上流側に、前記Ｇ－Ｔアナライザ２０を配置してもよいし、前記第一Ｇ－Ｔアナライザ７０および前記第二Ｇ－Ｔアナライザ７１を配置してもよい。前記Ｇ－Ｔアナライザ２０を配置する場合、λ／４板１５，２１を設けてもよい。また、本変形例において、一方の直線偏光成分と他方の直線偏光成分とを別々に記録して、その記録に基づいて後から計算で像を取得してもよい。 Therefore, according to this modification, the reflected light is separated into two directions of linearly polarized light components and detected respectively, and the difference between the light intensities of the two linearly polarized light components is divided by the sum of the light intensities of the two linearly polarized light components. Therefore, the influence of a change in light intensity such as a decrease in incident light source can be suppressed. Thereby, only the deflection change is extracted and corrected, and only the magnetic Kerr effect can be measured. That is, according to the present modification, background noise can be subtracted, and information on near-field light that is a measurement target can be more reliably extracted. In this modification, the GT analyzer 20 may be disposed upstream of the narrowband interference filter 18, and the first GT analyzer 70 and the second GT analyzer 71 may be disposed. You may arrange. When the GT analyzer 20 is disposed, λ / 4 plates 15 and 21 may be provided. Moreover, in this modification, one linearly polarized light component and the other linearly polarized light component may be recorded separately, and an image may be obtained later by calculation based on the recording.
　前記実施例や前記変形例において、対物レンズ６、結像レンズ２７およびカメラ３０を備える光学顕微鏡を用いてもよい。この場合、光学顕微鏡の倍率は、高倍率とされるのが好ましく、たとえば約１０００倍とされるのが好ましい。光学顕微鏡の倍率を高倍率とすることで、試料８の観察位置、およびレーザ光源１２からの磁区検出レーザ光の照射位置をモニタすることができ、これにより、計測対象である試料８の磁区の検出精度を向上させることができる。また、前記実施例や前記変形例において、金属製の膜１０は、金、銀、アルミの他、白金や銅であってもよい。また、前記実施例において、λ／４板１５，２１が設けられていない直線偏光の系では、近接場光成分を抜き出す際に、カンチレバー３の励振に同期したロックイン検出がなされる。 In the embodiment and the modification, an optical microscope including the objective lens 6, the imaging lens 27, and the camera 30 may be used. In this case, the magnification of the optical microscope is preferably a high magnification, for example, about 1000 times. By setting the magnification of the optical microscope to a high magnification, the observation position of the sample 8 and the irradiation position of the magnetic domain detection laser light from the laser light source 12 can be monitored, and thereby the magnetic domain of the sample 8 to be measured can be monitored. Detection accuracy can be improved. Moreover, in the said Example and the said modification, the metal films | membranes 10 may be platinum and copper other than gold | metal | money, silver, and aluminum. In the above embodiment, in the linearly polarized light system in which the λ / 4 plates 15 and 21 are not provided, lock-in detection synchronized with the excitation of the cantilever 3 is performed when extracting the near-field light component.
　　１　近接場偏光顕微鏡
　　２　探針
　　３　カンチレバー
　　４　磁区検出光学系
　　５　観察照明光学系
　　６　対物レンズ
　　７　磁界印加手段
　　８　試料
　１０　膜
　１１　磁区検出レーザ光
　１７　検出装置
　２７　結像レンズ
　２８　観察装置
　２９　照明光
　３０　カメラ
　４３　上部磁極
　４４　下部磁極
　７０　第一Ｇ－Ｔアナライザ
　７１　第二Ｇ－Ｔアナライザ
　７２　偏光ビームスプリッタ DESCRIPTION OF SYMBOLS 1 Near field polarizing microscope 2 Probe 3 Cantilever 4 Magnetic domain detection optical system 5 Observation illumination optical system 6 Objective lens 7 Magnetic field application means 8 Sample 10 Film 11 Magnetic domain detection laser beam 17 Detection device 27 Imaging lens 28 Observation device 29 Illumination light 30 Camera 43 Upper magnetic pole 44 Lower magnetic pole 70 First GT analyzer 71 Second GT analyzer 72 Polarizing beam splitter

Claims (8)

  1. 　少なくとも表面が磁性を有する試料の磁区を検出することができる近接場偏光顕微鏡であって、
    　非磁性材料から形成され、先端へ行くに従って先細りとなる凹形状の探針を有し、この探針は、誘電体で形成されると共に内面が金属製の膜で覆われ、前記探針と前記試料との間に原子間力が作用するよう配置されるカンチレバーと、
    　磁区検出レーザ光の前記探針内面への照射による近接場光により、前記試料の磁区を検出できる磁区検出光学系と、
    　前記磁区検出レーザ光の波長以外の波長帯を有する照明光の前記カンチレバーからの戻り光の光学像により、前記磁区検出レーザ光の照射状態が観察できる観察照明光学系と、
    　前記磁区検出光学系および前記観察照明光学系に対して共通に設けられる対物レンズと、
    　前記カンチレバーおよび前記試料を挟んで上下に配置される上部磁極および下部磁極を有し、前記試料に外部から磁界を印加することができる磁界印加手段と
    　を備えることを特徴とする近接場偏光顕微鏡。     A near-field polarization microscope capable of detecting a magnetic domain of a sample having at least a surface having magnetism,
    The probe is formed of a non-magnetic material and has a concave probe that tapers toward the tip. The probe is formed of a dielectric and has an inner surface covered with a metal film. A cantilever arranged such that an atomic force acts between the sample and the sample;
    A magnetic domain detection optical system capable of detecting a magnetic domain of the sample by near-field light by irradiation of the probe inner surface with a magnetic domain detection laser beam;
    An observation illumination optical system capable of observing the irradiation state of the magnetic domain detection laser light by an optical image of the return light from the cantilever of the illumination light having a wavelength band other than the wavelength of the magnetic domain detection laser light;
    An objective lens provided in common for the magnetic domain detection optical system and the observation illumination optical system;
    A near-field polarization microscope comprising: an upper magnetic pole and a lower magnetic pole arranged above and below the cantilever and the sample, and a magnetic field applying unit capable of applying a magnetic field from the outside to the sample.
  2. 　前記試料を２次元平面内で走査させる走査手段と、
    　この走査手段により設定量ずつ前記試料を移動させ、その各点におけるｚ座標を記録する座標記録手段と、
    　設定値間において外部磁界を変動させる磁界変動手段と、
    　前記各点において外部磁界を変動させた際の情報を記憶する記憶手段とをさらに備え、
    　前記磁区検出光学系からの前記情報に基づいて、前記試料の微小領域の磁気ヒステリシスを測定することができる
    　ことを特徴とする請求項１に記載の近接場偏光顕微鏡。     Scanning means for scanning the sample in a two-dimensional plane;
    A coordinate recording means for moving the sample by a set amount by the scanning means and recording the z coordinate at each point;
    Magnetic field changing means for changing the external magnetic field between set values;
    Storage means for storing information when the external magnetic field is changed at each of the points;
    The near-field polarization microscope according to claim 1, wherein magnetic hysteresis of a minute region of the sample can be measured based on the information from the magnetic domain detection optical system.
  3. 　前記下部磁極の上端部は、上方へ行くに従って先細りに形成される
    　ことを特徴とする請求項１または請求項２に記載の近接場偏光顕微鏡。     The near-field polarization microscope according to claim 1, wherein an upper end portion of the lower magnetic pole is formed to taper as it goes upward.
  4. 　前記磁区検出光学系は、消光可能なポラライザを二つ備える
    　ことを特徴とする請求項１～３のいずれか１項に記載の近接場偏光顕微鏡。     The near-field polarization microscope according to any one of claims 1 to 3, wherein the magnetic domain detection optical system includes two quenchable polarizers.
  5. 　前記ポラライザは、前記試料で反射された前記近接場光とそれ以外の光とを含む光から、前記それ以外の光を消光させて、前記試料で反射された前記近接場光と前記それ以外の光とを分離することができるＧ－Ｔアナライザとされ、
    　前記試料で反射された近接場光と前記それ以外の光とを含む光の進行方向において、一方の前記Ｇ－Ｔアナライザよりも下流側に他方の前記Ｇ－Ｔアナライザが配置され、
    　前記探針と前記試料との間の原子間力が無視できる程度に小さくなるよう前記試料の磁区検出時よりも前記探針が前記試料から離された状態において、前記磁区検出光学系が備える光の検出装置で検出される光が最小となるように一方の前記Ｇ－Ｔアナライザおよび他方の前記Ｇ－Ｔアナライザが調整され、その調整後、前記探針が前記試料に接触されるコンタクト状態、または前記探針と前記試料との間に形成される隙間が維持されるノンコンタクト状態において、他方の前記Ｇ－Ｔアナライザが回転されて前記検出装置で検出される光強度が最小値と最大値との間となるように設定される
    　ことを特徴とする請求項４に記載の近接場偏光顕微鏡。     The polarizer is configured to extinguish the other light from the light including the near-field light reflected by the sample and the other light, so that the near-field light reflected from the sample and the other light are reflected from the sample. It is a GT analyzer that can separate light,
    The other GT analyzer is disposed downstream of one GT analyzer in the traveling direction of the light including the near-field light reflected by the sample and the other light;
    The light included in the magnetic domain detection optical system in a state in which the probe is further away from the sample than when the magnetic domain of the sample is detected so that the atomic force between the probe and the sample is negligibly small. One GT analyzer and the other GT analyzer are adjusted so that the light detected by the detector is minimized, and after the adjustment, the probe is in contact with the sample; Alternatively, in a non-contact state in which a gap formed between the probe and the sample is maintained, the light intensity detected by the detection device when the other GT analyzer is rotated is a minimum value and a maximum value. The near-field polarization microscope according to claim 4, wherein the near-field polarization microscope is set so as to be between.
  6. 　前記磁区検出光学系は、前記試料で反射された前記近接場光とそれ以外の光とが含まれる光を、二つの方向の直線偏光成分に分離することができる偏光ビームスプリッタを備え、
    　一方の前記直線偏光成分の光強度と他方の前記直線偏光成分の光強度との差分を、一方の前記直線偏光成分の光強度と他方の前記直線偏光成分の光強度との和分で割る
    　ことを特徴とする請求項１～５のいずれか１項に記載の近接場偏光顕微鏡。     The magnetic domain detection optical system includes a polarization beam splitter capable of separating light including the near-field light reflected by the sample and other light into linearly polarized light components in two directions,
    Dividing the difference between the light intensity of one linearly polarized light component and the light intensity of the other linearly polarized light component by the sum of the light intensity of one linearly polarized light component and the light intensity of the other linearly polarized light component. The near-field polarizing microscope according to claim 1, wherein
  7. 　前記観察照明光学系は、結像レンズおよびカメラを備え、
    　前記対物レンズ、前記結像レンズおよび前記カメラを備える光学顕微鏡の倍率が約１０００倍とされる
    　ことを特徴とする請求項１～６のいずれか１項に記載の近接場偏光顕微鏡。     The observation illumination optical system includes an imaging lens and a camera,
    The near-field polarizing microscope according to any one of claims 1 to 6, wherein a magnification of an optical microscope including the objective lens, the imaging lens, and the camera is about 1000 times.
  8. 　前記磁区検出光学系は、
    　前記試料で反射された前記近接場光とそれ以外の光とを含む光から、前記それ以外の光を消光させて、前記試料で反射された前記近接場光と前記それ以外の光とを分離することができるＧ－Ｔアナライザ一つと、
    　光を検出することができる検出装置とを備え、
    　前記探針と前記試料との間の原子間力が無視できる程度に小さくなるよう前記試料の磁区検出時よりも前記探針が前記試料から離された状態において、前記検出装置で検出される光が最小となるように前記Ｇ－Ｔアナライザが調整され、その調整後、前記探針が前記試料に接触されるコンタクト状態、または前記探針と前記試料との間に形成される隙間が維持されるノンコンタクト状態において、前記試料の磁区の検出が行われる
    　ことを特徴とする請求項１～３のいずれか１項に記載の近接場偏光顕微鏡。     The magnetic domain detection optical system is
    From the light including the near-field light reflected by the sample and other light, the other light is quenched to separate the near-field light and the other light reflected from the sample. One GT analyzer that can
    A detection device capable of detecting light,
    Light detected by the detection device in a state in which the probe is further away from the sample than at the time of detecting the magnetic domain of the sample so that the atomic force between the probe and the sample is negligibly small. The GT analyzer is adjusted so as to minimize the gap, and after the adjustment, the contact state in which the probe comes into contact with the sample or the gap formed between the probe and the sample is maintained. 4. The near-field polarization microscope according to claim 1, wherein the magnetic domain of the sample is detected in a non-contact state.
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CN107621552A (en) * 2016-07-15 2018-01-23 中国科学院理化技术研究所 A kind of Polarization Modulation scanning near-field optical microscopy system device based on cantilever style circular hole probe
CN111257802A (en) * 2020-01-16 2020-06-09 上海科技大学 Method for realizing ferromagnetic magnetic domain morphology construction by utilizing magneto-optical effect
EP3835797A1 (en) * 2019-12-11 2021-06-16 Université de Genève Magnet device

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CN107621552A (en) * 2016-07-15 2018-01-23 中国科学院理化技术研究所 A kind of Polarization Modulation scanning near-field optical microscopy system device based on cantilever style circular hole probe
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CN111257802B (en) * 2020-01-16 2022-06-21 上海科技大学 Method for realizing ferromagnetic magnetic domain morphology construction by utilizing magneto-optical effect

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