JP4298233B2 - Near-field light source device, optical head having the near-field light source device, exposure apparatus, and microscope apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an apparatus related to near-field light, and more particularly to a near-field light source device that generates near-field light, and an optical head having the near-field light source device., DewThe present invention relates to an optical device and a microscope device.
[0002]
[Prior art]
Recently, optical technology using evanescent light that oozes out from a fine aperture of about 100 nm or less at the tip of a sharp probe, high-resolution observation using a so-called near-field (near-field or near-field) optical system, and high-density recording for the next generation The development of ultra-fine exposure technology has become active. For high-resolution observation, a scanning near-field optical microscope (hereinafter abbreviated as SNOM) that examines a sample surface by detecting the state of the sample surface with an optical probe (Durig et al., J. Appl. Phys., Vol. 59, 3318 (1986) etc.) have been developed.
[0003]
As a near-field light source device used for these, for example, Japanese Patent Laid-Open No. 5-100168 discloses the following. Here, as shown in FIG. 9, a minute opening 910 is formed at the tip of a conical member provided on the Si substrate 901, and an opening 902 is formed on the back side of the Si substrate 901, and an optical fiber 903 is formed there. Is inserted through which light is emitted. In FIG. 9, reference numeral 907 denotes an electrode, 908 denotes an optical waveguide layer, 909 denotes a metal film, and 911 denotes an antireflection film.
Japanese Patent Application Laid-Open No. 10-143895 also shows that an ultrafine hole 1004 is formed in a light emitting portion 1003 of a surface emitting laser (VCSEL) as shown in FIG. In FIG. 10, reference numeral 1001 denotes a VCSEL element, and 1002 denotes a laser substrate including a multilayer reflective film and a laser active layer.
[0004]
Further, Japanese Patent Application Laid-Open No. 9-145603 proposes one having an inhomogeneous laser emission surface 1102 on one end surface of an edge-emitting semiconductor laser 1100 as shown in FIG. The concave portion 1106 of the multilayer film 1102 has a width of ½ or less of the laser wavelength, from which at least 50% of the total radiation is emitted. In FIG. 11, reference numeral 1101 denotes a ridge waveguide, 1103 denotes a back facet, 1104 denotes a dielectric portion of the emission surface coating, 1105 denotes a conductor portion of the emission surface coating, and 1107 denotes radiation emitted through the recess.
[0005]
[Problems to be solved by the invention]
Incidentally, since the near-field optical system uses an evanescent wave that oozes out from a minute aperture, the efficiency of the light source is required, and a semiconductor laser having a low threshold and high quantum efficiency is required. However, as shown in FIG. 9, an optical coupling part for guiding light through the optical fiber 903 or the like tends to cause coupling loss and there is room for improvement. Further, in the SNOM head using the edge emitting laser as shown in FIG. 11, it is difficult to shorten the element length because the edge reflectance is not high. For this reason, the operating current is reduced to reduce the power consumption. There are limits.
[0006]
In addition, when a minute aperture is formed on the emission end face of the surface emitting laser as shown in FIG. 10, if the minute aperture is formed on a mirror having a high reflectivity, the high reflectivity mirror has a reflectivity with respect to the return light. Since it is high, when it is used as a self-coupled optical pickup that couples the return light from the optical disk to the resonator again, the coupling efficiency becomes small. Therefore, in order to increase the coupling efficiency with respect to the return light, it is necessary to lower the reflectivity of the mirror at the expense of the laser performance.
[0007]
  Therefore, the present invention can generate an optical near field efficiently, perform a low threshold operation, and improve the coupling efficiency with return light, and the near field light source device Optical head with, DewAn object of the present invention is to provide an optical device and a microscope device.
[0008]
[Means for Solving the Problems]
  The present invention provides the following (1) to (5), A near-field light source device, an optical head having the near-field light source device, an exposure device, and a microscope device.
(1) A near-field light source device that generates near-field light,
  A ring resonator type semiconductor laser configured by laminating a semiconductor layer on a substrate surface;
  Ring resonator type semiconductor laserThe ring resonator in is circular in shape,
  CircularA light-shielding film disposed in contact with the outer periphery of the ring resonator;
  A slit-shaped minute opening whose longitudinal direction formed in the light-shielding film is perpendicular to the substrate surface;
  Have
  A near-field light source device that generates near-field light having an electric field vector parallel to the substrate surface from the minute aperture.
(2) The near-field light source device according to (1), wherein the light shielding film is formed of a multilayer film made of a dielectric film and a metal film.
(3) A slider having the near-field light source device described in (1) above is provided, the slider is levitated on the surface of the optical recording medium, and recording / reproducing / erasing is performed using near-field light generated from the minute aperture. A floating optical head characterized by
(4) An exposure comprising a cantilever that supports the near-field light source device according to (1), wherein the cantilever is brought close to a wafer stage, and exposure is performed using near-field light generated from the minute aperture. apparatus.
(5) Having a cantilever that supports the near-field light source device according to (1), bringing the cantilever close to a sample stage, and irradiating the sample with near-field light generated from the minute aperture to observe the sample A microscope apparatus characterized by the above.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
By configuring the near-field light source device by applying the above configuration, the spread of the evanescent wave generated in the low refractive index portion near the resonator due to the total reflection of the ring resonator is limited by the light shielding film and the opening provided in the light shielding film. Thus, it is possible to generate an optical near field with a small spot size.
In constructing the flying optical head, the near-field light source device having the above-described configuration is mounted on a slider, and the slider is floated on the surface of the optical recording medium, and recording / reproduction / erasure is performed with light generated in the vicinity of the opening. An optical head to perform can be realized. As a result, a light source that generates an optical near field with a small spot size by limiting the spread of the evanescent wave generated in the low refractive index portion near the resonator due to total reflection of the ring resonator by the light shielding film and the opening provided in the light shielding film. , And a slider equipped with the same is floated and brought close to the surface of the optical recording medium, so that an optical near field having a small spot size can be generated on the recording medium and recording / reproducing / erasing can be performed. Similarly, an optical device that performs recording and reproduction with light generated in the vicinity of the opening can be realized.
Further, when configuring the exposure apparatus, an exposure apparatus is realized in which the near-field light source device having the above-described configuration is supported by a cantilever, is brought close to the wafer stage, and exposure is performed with light generated near the opening of the light source. Can do. This makes it possible to form an arbitrary pattern by two-dimensionally scanning a light spot below the diffraction limit on a wafer coated with a photoresist film and exposing the photoresist film.
Further, when configuring the microscope apparatus, a microscope apparatus for observing the sample by irradiating the sample with light generated in the vicinity of the opening by supporting the near-field light source device having the above configuration with a cantilever and bringing it close to the sample stage. Can be realized. As a result, a fine structure can be observed by two-dimensionally scanning a light spot below the diffraction limit on the sample and detecting scattered light therefrom.
[0010]
Next, the near-field light source device according to the embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing the configuration of this embodiment, which will be described later. In FIG. 1, 100 is a near-field light source device, 101 is a ring resonator type semiconductor laser, 102 is a multilayer film that is a light shielding film, and a dielectric film 103. And a metal film 104. Reference numeral 105 denotes a minute opening formed in the metal film 104.
[0011]
First, a ring resonator type semiconductor laser without the light shielding film 102 will be briefly described. An optical resonator of a ring resonator type semiconductor laser is composed of a plurality of linear optical waveguides and a corner mirror connecting them. In the case of a square ring resonator as shown, the angle of incidence on the corner mirror is 45 degrees. For example, in the case of an AlGaAs / GaAs compound semiconductor laser, the critical angle of total reflection at the semiconductor / air interface is 17 degrees with respect to the effective refractive index of 3.3 in the waveguide mode, and the incident angle to the corner mirror is Since it is large, it becomes total reflection.
Since the light emitted outside the resonator is small and the loss is small, a low threshold semiconductor laser can be constructed. At this time, an evanescent field that decays exponentially with respect to the distance from the total reflection surface is generated on the low refractive index side of the total reflection surface.
[0012]
Next, a case where there is a multilayer film as a light shielding film on the corner mirror as in such a semiconductor ring laser will be described. When the total reflection condition is satisfied at the interface between the dielectric film as the first layer of the multilayer film and the semiconductor as in the previous example, an evanescent field is generated by the total reflection here. An opening 105 having a size smaller than the spot size of the guided light is formed in the metal film 104 that is the second layer of the multilayer film. This opening restricts the expansion of the evanescent field due to the total reflection, and an evanescent field having a small lateral expansion can be generated in the vicinity of the opening 105.
[0013]
FIG. 4 is a diagram showing a partial configuration of a floating optical pickup for recording / reproducing using a near-field light source device in an embodiment of the present invention to be described later. In FIG. 4, 401 is a magneto-optical disk or an optical disk such as a minute pit and phase change recording. Reference numeral 402 denotes a slider, which is lifted and held by a predetermined interval from the disk 401 by an arm (not shown). Here, the predetermined interval is generally equal to or smaller than the size of the opening of the near-field light source device. The slider 402 reciprocates within a predetermined range on the optical disc 401 by an actuator (not shown).
[0014]
A near-field light source device 403 is mounted on the slider 402, and when a ring resonator type semiconductor laser of the near-field light source device oscillates, a minute light spot is formed on the optical disk. The change in the reflection characteristic of the optical disk changes the amount of return light that is again coupled to the optical resonator through the minute aperture. In the case of a magneto-optical disk, the amount of light coupled to the laser mode changes due to the rotation of the polarization plane of the return light. This change in the amount of return light can be detected by a principle known as a self-coupled optical pickup (SCOOP). That is, when the return light is coupled to the optical resonator, the light intensity in the semiconductor laser fluctuates, and this is detected. The fluctuation of the light intensity can be detected by a light receiving element provided near another corner mirror, or can be detected from a voltage fluctuation between terminals of the semiconductor laser.
[0015]
【Example】
Examples of the present invention will be described below.
[Example 1]
FIG. 1 is a diagram showing a near-field light source device in Embodiment 1 of the present invention. With reference to FIG. 1, a method for forming a near-field light source device and a driving method thereof in the present embodiment will be described. In FIG. 1, 100 is a near-field light source device in this embodiment, 101 is a ring resonator type semiconductor laser, 102 is a multilayer film which is a light shielding film, and is composed of a dielectric film 103 and a metal film 104. Reference numeral 105 denotes a minute opening formed in the metal film 104.
[0016]
The near-field light source device 100 was produced as follows. First, a semiconductor multilayer structure shown in the element cross-sectional view A-A ′ was formed by metal organic vapor phase epitaxy. That is, an n-AlGaAs cladding layer 112, an AlGaAs / AlGaAs quantum well active layer 113, a p-AlGaAs cladding layer 114, and a p-GaAs cap layer 115 were grown on the n-GaAs substrate 111. A photoresist was applied, and the mask pattern was exposed and developed to form a ring resonator-shaped resist pattern.
[0017]
A part of the p-cladding layer 114 was removed by reactive ion etching using chlorine gas to form a ring-shaped ridge waveguide. For example, the remaining thickness of the p-cladding is 0.1 μm. Subsequently, a mask pattern of the corner mirror portion was formed again, and etching was performed about 1 μm deeper than the active layer, and a corner mirror was formed as shown in FIG. B-B ′ cross section. Since the waveguide mode is wider than the ridge width, the corner mirror width is larger than the width of the ridge waveguide. SiNx was formed as the dielectric films 116 and 103, and a contact window was opened only on the ridge. At this time, the thickness of the dielectric film 103 on the corner mirror surface was set to 100 nm. Cr / Au is vapor-deposited to form a p-electrode 117 and a light shielding film second layer metal film 104. Further, Cr was formed on the entire surface, Au was obliquely deposited, and 104 was the only metal film in the second light shielding film.
[0018]
AuGe / Ni / Au is deposited on the lower side of the wafer to form the n-electrode 110. The alloy is formed in a hydrogen atmosphere, and the interface between the p and n electrodes and the semiconductor is brought into ohmic contact. Cleave the wafer at the corner mirror position. A part of the metal film 104 on the corner mirror is removed by FIB processing to form a fine opening.
When the p-electrode 117 and the n-electrode 110 were connected to a laser drive driver and driven with a constant current exceeding the oscillation threshold current, the ring resonator type semiconductor laser 101 oscillated.
[0019]
In the case of an element having a structure in which the entire surface is covered with a metal electrode as in this embodiment, the laser oscillation threshold is confirmed as a kink of the I-dV / dI curve in which the current I and the differential resistance dV / dI of the element are plotted. it can. Alternatively, scattered light from the corner mirror can be extracted to the far field by removing a part of the electrodes of the corner mirror portion to form a light extraction window. For an element in which a light extraction window is formed in this way, the oscillation threshold current is measured as a bend of the IL curve in which the current I and the light output L are plotted as in the case of a normal edge emitting semiconductor laser. I was able to. However, since the light output at this time is due to the scattered light from the total reflection mirror, it is extremely small, about 1/1000 compared with the light output of a normal edge emitting laser.
[0020]
In order to use the light emitted in this way as a monitor of the light intensity in the resonator, light receiving elements 503 and 504 may be arranged near the corner mirror as shown in FIG. As shown in FIG. 6, the light receiving elements 603 and 604 may be integrated on the same substrate.
[0021]
Thus, when the ring resonator type semiconductor laser 101 is oscillating, the light in the resonator is coexisting with clockwise light and counterclockwise light. The clockwise light and the counterclockwise light are coupled by backscattering in the corner mirror part or the waveguide part. In the corner mirror portion, an evanescent wave is generated by total reflection of these lights, but the lateral spread along the corner mirror surface is limited by the opening. Thus, an optical near field is generated only in the vicinity of the opening. The shape of the opening may be circular or an elongated slit. For example, in a light source used for reading an optical disk, the length of the slit may be smaller than the track interval on the optical disk.
[0022]
Furthermore, when the polarization of the laser mode is the TE mode (the electric field vector is parallel to the substrate), the electric field vector of the evanescent field is also parallel to the substrate. Therefore, by making the longitudinal direction of the slit-shaped minute aperture perpendicular to the substrate The amount of light transmitted through the minute slit can be increased.
In this embodiment, an example using an AlGaAs / GaAs semiconductor laser is shown. However, an InGaN / GaN system having a wavelength of around 400 nm, a GaInP / GaAs system having a wavelength of 650 nm, an InGaAs / GaAs system having a wavelength of 980 nm, 1.3 to 1 The semiconductor laser may be made of any material such as an InGaAsP / InP system or GaInNAs / GaAs system in the .55 μm band.
[0023]
[Example 2]
FIG. 2 is a diagram illustrating the near-field light source device according to the second embodiment of the present invention.
In FIG. 2, reference numeral 200 denotes a near-field light source device according to the present embodiment, 201 denotes a ring resonator type semiconductor laser, and 202 denotes a multilayer film that is a light shielding film, which includes a dielectric film 203 and a metal film 204. Reference numeral 205 denotes a minute opening formed in the metal film 204.
[0024]
The ring resonator type semiconductor laser device 201 was manufactured as follows. First, a semiconductor multilayer structure shown in the element cross-sectional view A-A ′ was formed by metal organic vapor phase epitaxy. That is, an n-AlGaInP cladding layer 212, a GaInP / AlGaInP quantum well active layer 213, a p-AlGaInP cladding layer 214, and a p-GaAs cap layer 215 were grown on the n-GaAs substrate 211. A photoresist was applied, and the mask pattern was exposed and developed to form a ring resonator-shaped resist pattern. In this embodiment, the ring resonator has a circular shape. The outside of the circular waveguide was etched about 1 μm deeper than the active layer. On the other hand, the inside of the circular waveguide has a current confinement and refractive index waveguide structure as shallow etching leaving a part of the upper cladding layer.
[0025]
SiNx was formed as the dielectric films 216 and 203, and a contact window was opened only on the ridge. Configurations of the p-electrode 217 made of Cr / Au, the n-electrode 210 made of AuGe / Ni / Au, and the like are the same as those in the first embodiment. The alloy is formed in a hydrogen atmosphere, and the interface between the p and n electrodes and the semiconductor is brought into ohmic contact. The wafer is cleaved at a position in contact with the circular waveguide, and a part of the metal film 204 on the corner mirror is removed by FIB processing to form a fine opening.
[0026]
The circular waveguide of the present embodiment is a circular ring resonator that is guided not only by the outer air / semiconductor interface but also by the refractive index difference due to the inner ridge structure. Here, at the outer air / semiconductor interface, an evanescent wave caused by total reflection occurs as in the first embodiment. The spread of the evanescent field is limited by the opening, and an optical near field is generated only in the vicinity of the opening.
[0027]
Further, when the diameter of the circular waveguide is reduced, a ring resonator using a whispering gallery mode guided only by the outer air / semiconductor interface can be formed. Also in this case, current narrowing by the ridge structure as described above is effective for lowering the threshold value of the semiconductor laser. Even in a ring resonator type semiconductor laser operating in whispering gallery mode, an evanescent wave caused by total reflection is generated at the outer air / semiconductor interface. An optical near field can be generated only in
[0028]
[Example 3]
FIG. 3 is a diagram illustrating the near-field light source device according to the third embodiment of the present invention.
In FIG. 3, reference numeral 300 denotes a near-field light source device according to the present embodiment, 301 denotes a ring resonator type semiconductor laser, 302 denotes a multilayer film which is a light shielding film, and includes a dielectric film 303 and a metal film 304. Reference numeral 305 denotes a minute opening formed in the metal film 304.
[0029]
This embodiment is a ring resonator type semiconductor laser having a layer configuration similar to that of Embodiment 1 and Embodiment 2, but the shape of the ring resonator is different, and the incident light is incident on a corner mirror that generates near-field light. The corner becomes small, and the semiconductor / dielectric film interface does not satisfy the total reflection condition. Here, SiN having a refractive index of 1.95 is formed as a dielectric film on a corner mirror of a regular triangular ring resonator._xA film is formed. For example, when the equivalent refractive index of the semiconductor layer is 3.3, the total reflection critical angle at the semiconductor / dielectric interface is 36 degrees, and the incident angle to the corner mirror is larger than 30 degrees. At this time, most of the light incident on the corner mirror is reflected at the semiconductor / dielectric interface, but part of the light enters the dielectric film 303 as propagating light and is reflected at the dielectric / metal interface.
[0030]
Moreover, a part of light passes through the opening at the minute opening. In Example 1, since it is an evanescent field from the total reflection interface, this dielectric film needs to be thinner than the wavelength. On the other hand, in this embodiment, such a restriction on the thickness of the dielectric film 303 is relaxed. However, the reflectivity of the corner mirror is a combination of the reflection at the semiconductor / dielectric interface and the reflection at the dielectric / metal interface, and the corner mirror reflectivity decreases as the dielectric film thickness increases. Therefore, it is preferable that the film thickness of the dielectric 303 is about 100 to 200 nm and at least thinner than the wavelength.
[0031]
In addition, light that has passed through the metal minute opening generates an optical near field only in the vicinity of the opening. When this embodiment is compared with the case where the semiconductor / dielectric interface satisfies the total reflection condition, the threshold value of the semiconductor laser increases due to a decrease in the reflectivity of the corner mirror. The intensity of the near-field light is increased by entering the distance. These differences are due to the difference in light behavior that the evanescent field of the semiconductor / dielectric interface starts in Example 1, whereas the near field starts to decay from the dielectric / metal interface in this example. Yes.
[0032]
[Example 4]
FIG. 4 is a diagram showing an optical head in Embodiment 4 of the present invention.
In FIG. 4, 401 is a magneto-optical disk or an optical disk such as a minute pit and phase change recording. Reference numeral 402 denotes a slider, which is lifted and held by a predetermined interval from the disk 401 by an arm (not shown). Here, the predetermined interval is generally equal to or smaller than the size of the opening of the near-field light source device. The slider 402 reciprocates within a predetermined range on the optical disc 401 by an actuator (not shown). A near-field light source device 403 is mounted on the slider 402, and when a ring resonator type semiconductor laser is oscillated, a minute light spot is formed on the optical disk.
[0033]
The change in the reflection characteristic of the optical disc 401 changes the amount of light returning to the optical resonator through the minute aperture. In the case of a magneto-optical disk, the amount of light coupled to the laser mode changes due to the rotation of the polarization plane of the return light. This change in the amount of return light can be detected by a principle known as a self-coupled optical pickup (SCOOP). That is, since the light intensity in the semiconductor laser is significantly changed by the return light, this is detected. The fluctuation of the light intensity can be detected by a light receiving element provided in the vicinity of a corner mirror different from the corner mirror that generates the near-field light, or can be detected from a voltage fluctuation between terminals of the semiconductor laser. In the latter case, when the light intensity fluctuation is detected from the voltage fluctuation between terminals, the semiconductor laser is driven at a constant current, and the voltage between terminals at this time may be directly monitored. Alternatively, only the fluctuation component may be monitored via a coupling capacitor.
[0034]
FIG. 5 shows a near-field light source device in which a light receiving element is provided in the vicinity of the corner mirror for the above purpose. Reference numeral 501 denotes a near-field light source device according to this embodiment, 502 denotes a light extraction corner mirror unit, 503 and 504 are light receiving elements, 505 is a dielectric film, and 506 is a metal film.
[0035]
The corner mirror 502 is a total reflection mirror similar to the near-field light source device described so far, but only the dielectric film 505 is formed on the mirror surface, and the metal film 506 is not formed. Therefore, the vicinity of the mirror is removed by etching so that scattered light radiated from the corner mirror surface in the direction of the arrow reaches the light receiving elements 503 and 504, and as shown in the CC ′ sectional view. In addition, the substrate is removed in the vicinity of the mirror. A change in the light intensity in the semiconductor laser due to the return light can be detected as a change in the amount of light reaching the light receiving elements 503 and 504. Therefore, information recorded as a change in reflectance on the optical disc 501 can be used as a change in the amount of light. Can be read out.
[0036]
FIG. 6 shows a near-field light source device in which a light receiving element in the vicinity of a corner mirror is integrated with a ring resonator type semiconductor laser. Reference numeral 601 denotes a near-field light source device according to the present embodiment, reference numeral 602 denotes a light extraction corner mirror, and reference numerals 603 and 604 denote light receiving elements.
The light receiving elements 603 and 604 have the same layer structure as that of the ring resonator type semiconductor laser. The bottom of the active layer is removed by etching simultaneously with the corner mirror formation, and the substrate is electrically separated from the active layer and above. A reverse bias is applied to the pn junction of the active layer to detect light emitted from the corner mirror as a pin light receiving element. By integrating the light receiving elements, the number of components can be reduced and the assembly process can be simplified.
[0037]
[Example 5]
FIG. 7 shows an exposure apparatus according to Embodiment 5 of the present invention.
In FIG. 7, 701 is a near-field light source device according to the present invention, 702 is a cantilever, 703 is a wafer stage, 704 is a piezo element, 705 is a semiconductor laser for position detection, 706 is a two-divided sensor, 707 is a wafer, and 708 is on the wafer. This resist film.
[0038]
A resist thin film 708 that is sensitive to near-field light in the vicinity of the minute opening of the near-field light source device 701 is coated on the wafer 707. The near-field light source device 701 is mounted on the cantilever 702, and the distance from the wafer stage 703 and the resist film 708 on the wafer surface placed thereon can be controlled by the piezo element 704. This distance was controlled according to the principle of an optical lever in which laser light from the position detecting semiconductor laser 705 was irradiated in the vicinity of the tip of the cantilever 702 and the reflected light was received by the two-divided sensor 706.
[0039]
A desired resist pattern is formed by turning on / off the near-field light by controlling the drive current of the near-field light source device 701 in accordance with the timing when the wafer stage 703 on which the wafer 707 is placed is scanned in a two-dimensional direction. be able to.
[0040]
[Example 6]
FIG. 8 is a diagram showing a microscope according to Example 6 of the present invention.
In FIG. 8, 801 is a near-field light source device according to this embodiment, 802 is a cantilever, 803 is a sample stage, 804 is a piezo element, 805 is a lens, 806 is an interference filter, 807 is a photodetector, and 808 is a sample.
The optical near field near the minute aperture of the near-field light source device 801 is irradiated from the front surface side of the sample, and the reflected and scattered light from the sample is collected by the lens 805, and is detected by the photodetector 807 via the interference filter 806. This is a SNOM having a so-called reflective oblique light detection configuration for detection. The near-field light source device 801 is mounted on a cantilever 802, and the distance from the wafer stage 803 and the sample 808 placed thereon can be controlled by a piezo element 804.
[0041]
Since the intensity of the optical near-field oozing from the minute aperture decreases exponentially with respect to the distance from the aperture, the tip of the optical probe is brought close to a distance of 100 nm or less with respect to the sample surface and kept at a constant distance. It is necessary to perform control. As a distance control method for this purpose, for example, there are the following methods (1) to (2).
(1) Shear force that controls the distance so that the optical probe is slightly vibrated in a direction perpendicular to the normal direction of the sample surface, and the decrease in vibration amplitude due to van der Waals force that the tip of the optical probe receives from the sample surface is made constant. method.
(2) The optical probe is supported by an elastic body that can be elastically deformed in the normal direction of the sample surface, and the elastic deformation amount of the elastic body generated by van der Waals force acting between the tip of the optical probe and the sample surface is constant. AFM system that controls the distance so that
[0042]
In such a manner, the distance between the optical probe and the sample is controlled, and the two-dimensional stage 803 to which the sample 808 is attached is driven to perform two-dimensional relative scanning with respect to the near-field light source device 801. The magnitude of the signal from the photodetector 807 at each position during the two-dimensional scanning is mapped, and a near-field optical microscope image of the sample surface is obtained.
[0043]
【The invention's effect】
  According to the present invention, a near-field light source device capable of efficiently generating an optical near-field, performing a low threshold operation, and improving the coupling efficiency with return light, and the near-field light source device Optical head with, DewAn optical device and a microscope device can be realized.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a near-field light source device according to a first embodiment of the invention.
FIG. 2 is a diagram for explaining a near-field light source device according to a second embodiment of the invention.
FIG. 3 is a diagram for explaining a near-field light source device according to Embodiment 3 of the present invention.
FIG. 4 is a diagram showing an optical head in Embodiment 4 of the present invention.
FIG. 5 is a plan view of a near-field light source device used in a floating optical pickup for recording / reproducing in an embodiment of the present invention.
FIG. 6 is a plan view of a near-field light source device used for a floating optical pickup for recording / reproducing in an embodiment of the present invention.
FIG. 7 is a view showing the arrangement of an exposure apparatus using a near-field light source device in Embodiment 5 of the present invention.
FIG. 8 is a diagram showing a configuration of a microscope using a near-field light source device in Example 6 of the present invention.
FIG. 9 is a diagram showing a near-field light source device in a conventional example.
FIG. 10 is a diagram showing a near-field light source device in a conventional example.
FIG. 11 is a diagram showing a near-field light source device in a conventional example.
[Explanation of symbols]
101, 201, 301: Ring resonator type semiconductor laser
102, 202, 302: light shielding film
103, 203, 303: Dielectric film
104, 204, 304: Metal film
105, 205, 305: Opening
401: Optical disc
402: Slider
403, 701, 801: Near-field light source device

Claims (5)

A near-field light source device for generating near-field light,
A ring resonator type semiconductor laser configured by laminating a semiconductor layer on a substrate surface;
The ring resonator in the ring resonator type semiconductor laser has a circular shape, and a light shielding film disposed in contact with the outer periphery of the circular ring resonator;
A slit-shaped minute opening whose longitudinal direction formed in the light-shielding film is perpendicular to the substrate surface;
Have
A near-field light source device that generates near-field light having an electric field vector parallel to the substrate surface from the minute aperture.   The near-field light source device according to claim 1, wherein the light-shielding film is formed of a multilayer film including a dielectric film and a metal film.   A slider having the near-field light source device according to claim 1 mounted thereon, wherein the slider is floated on the surface of the optical recording medium, and recording / reproducing is erased using near-field light generated from the minute aperture. A floating optical head.   An exposure apparatus comprising a cantilever that supports the near-field light source device according to claim 1, wherein the cantilever is brought close to a wafer stage, and exposure is performed using near-field light generated from the minute aperture. .   A cantilever that supports the near-field light source device according to claim 1, wherein the cantilever is brought close to a sample stage, and the sample is observed by irradiating the sample with near-field light generated from the minute aperture. Microscope device.

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