JP3474833B2 - Near-field light detection optical system, near-field optical device, near-field optical microscope, optical information reproducing device, and optical information detection method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a near-field light detecting optical system for detecting optical information on the surface of a subject by using near-field light, a near-field optical device equipped with this optical system, and the use thereof. The method for detecting optical information on the surface of a subject is applied to a near-field optical microscope or an optical information reproducing device.

[0002]

2. Description of the Related Art An optical microscope narrows a light beam through a focusing system and irradiates the surface of a subject to observe an image of the surface.
The optical microscope has been used for a long time as a relatively simple and inexpensive high-resolution surface observation means. The optical information reproducing device narrows a light beam through a light converging system and irradiates a recording medium as an object to optically reproduce information.
The optical information reproducing device is widely used as a large-capacity, high-speed, medium exchangeable, low-cost storage device.

The resolution of these optical devices is limited by the spot size of the light beam that illuminates the subject. The light spot size means the diameter of the portion where the intensity decreases to e ⁻² of the central intensity of the Gaussian light beam profile. In an optical device that uses a condensing system that uses an ordinary objective lens,
The size of the light spot on the subject is determined by the monochromaticity of the light source, the wavelength, and the numerical aperture (NA) of the lens. For example, a wavelength of 400n, which is planned to be used in the next-generation optical recording device.
m blue-violet laser and NA: 0.6 objective lens, the light spot size is about 0.55 μm, and the distinguishable scale is 1/2 of this spot size.
Limited to the extent.

In recent years, near-field light has attracted attention as a new light-collecting method that overcomes the limit of the detection resolution of the light-collecting system using the ordinary objective lens as described above. The near-field light is a non-propagating electromagnetic field (evanescent field) formed in the vicinity of the minute optical aperture. The micro-optical aperture is provided in the light emitting portion of the optical probe, and the periphery of the optical aperture is preferably covered with a reflector. This is to prevent light leaked from a portion other than the opening from entering the subject. When the surface of the subject is placed close to the evanescent field, a scattered scattered light is generated due to the near field interaction.
Since the intensity or phase of the scattered light bears optical information on the surface of the subject, the information on the surface of the subject can be obtained by ordinary detecting means.

The resolution when using near-field light is determined by the size of the evanescent field. For example, when the tip of the optical fiber is narrowed down and the tip is covered with a reflector such as metal leaving an optical aperture of several tens of nm, the resolution can be set to several tens of nm, which is about the same as that of the optical aperture. Therefore, the resolution is remarkably improved as compared with the conventional focusing system using an objective lens.

From such a background, there is known a report example in which recording / reproduction is attempted by irradiating a magneto-optical recording medium with near-field light by using an optical aperture or a solid immersion lens (SIL).

For example, Japanese Laid-Open Patent Publication No. 10-269614 has a protrusion for scattering near-field light generated near the surface of a recording medium, and a photodiode for converting the scattered near-field light into an electric signal. There is disclosed a polarized near-field light detection head in which a protrusion and a photodiode are integrally formed on a support, and an analyzer is provided between the protrusion and the photodiode in contact with the photodiode. In this publication, incident light is irradiated from the lower surface of the recording medium at an incident angle equal to or greater than a critical angle to generate near-field light near the surface of the recording medium, and a protrusion is generated in the near-field light generated near the surface of the recording medium. Are arranged. However, when the incident optical system is arranged on the lower surface side of the recording medium and the detection system is arranged on the front surface side as in this publication, it is obvious that the apparatus becomes complicated.

Therefore, by using an optical probe having an optical aperture and a reflector covering the periphery thereof, irradiating the subject with incident light through the optical probe, and detecting the reflected light from the subject through the optical probe, the device configuration is obtained. It is thought that it can be simplified. However, such a device configuration has not been reported so far.

This is because the noise level becomes extremely high when reflection type detection is performed in which the incident light is applied to the subject through the optical probe and the reflected light from the subject is detected through the optical probe as described above. This is because there is a problem that the contrast tends to be unclear.

The present inventors have found that the reason why the noise level becomes high when the above reflection type detection is performed is that the use efficiency of incident light is essentially low when using near-field light, and the background noise is low. It has been found that in addition to being easily affected by the above, in the reflection type detection, the reflection signal from the back surface of the reflector coated on the probe tip is superimposed on the reflection signal from the subject.

[0011]

SUMMARY OF THE INVENTION It is an object of the invention to provide a low noise level due to reflective detection using an optical aperture,
Another object of the present invention is to provide a near-field optical device such as a near-field optical microscope or an optical information reproducing device that can obtain a clear optical contrast.

[0012]

A near-field light detecting optical system according to the present invention comprises a light source and a light source which emits light directly from the light source.
A means to generate linearly polarized light and an optical aperture at the tip and its surrounding
The linearly polarized light has a structure in which a reflector for coating is provided.
The near-field light from the optical aperture by guiding the
The light incident on the body surface and reflected from the subject is the light
With an optical probe that guides light through the aperture and an analyzer
The reflected light that has passed through the optical probe to the analyzer.
A detecting element for detecting through
Background reflected from the reflector near the optical aperture
Characterized by being adjusted to selectively block light
And

A near-field optical device according to the present invention comprises a light source,
Means for producing linearly polarized light from light emitted from said light source
And a reflector that covers the optical aperture and its surroundings is provided at the tip.
The linearly polarized light is guided by the optical opening.
Generate near-field light from the mouth and make it incident on the surface of the subject, and
Guide reflected light from the subject through the optical aperture
With an optical probe and an analyzer,
Detecting element for detecting reflected light that has passed through the analyzer
And the analyzer is a reflector near the optical aperture.
It selectively blocks the background light reflected from
It is tuned as follows.

The near-field optical microscope according to the present invention comprises a light source
And generate linearly polarized light from the light emitted from the light source.
Means and the reflector that covers the optical aperture and its surroundings at the tip
It has a structure provided to guide the linearly polarized light
The near-field light is generated from the optical aperture and enters the subject surface,
In addition, the reflected light from the subject is guided through the optical aperture.
The optical probe, which has a wavy optical probe and an analyzer.
Detection of detecting reflected light passing through the probe through the analyzer
An element, wherein the analyzer reflects light near the optical aperture.
Selectively blocks background light reflected from the body
It is adjusted so that Also,
The optical information reproducing device according to Ming
A means to generate linearly polarized light from the emitted light and a light at the tip
A structure with a reflector that covers the aperture and its surroundings
Having a near-field from the optical aperture by guiding the linearly polarized light.
Light is generated and is incident on the surface of the medium, and is emitted from the medium.
Optical probe for guiding reflected light through the optical aperture
And a reflected light having an analyzer and passing through the optical probe.
And a detection element for detecting through the analyzer,
The analyzer is a beam reflected from the reflector near the optical aperture.
Tuned to selectively block background light
It is characterized by being

In the method of detecting optical information on the surface of a subject according to the present invention, the tip has an optical aperture and a reflector covering the periphery thereof.
Using an optical probe having the structure provided,
The linearly polarized light is guided to the probe and the near field is emitted from the optical aperture.
Light is generated and is incident on the surface of the subject, and
Reflected light through the optical aperture to the optical probe
It is guided by a detector and is detected by a detector.
When detecting the optical information on the surface of the sample,
A photon is reflected by a reflector near the optical aperture.
Adjust to selectively block ground light
Is characterized by.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a conventional magneto-optical recording / reproducing apparatus using far-field light, a method of using linearly polarized light for reproduction light and using an analyzer for a detection system has already been implemented. The reason for irradiating the magneto-optical medium with the linearly polarized light is that the magneto-optical effect that the plane of polarization of the reflected light is rotated according to the magnetization direction of the magneto-optical medium is used as a reproducing principle.

On the other hand, conventionally, linearly polarized light is not used for an object that does not exhibit a magneto-optical response. This is because it is possible to detect an optical change with ordinary circularly polarized light as it is, and when linearly polarized light is used, it is necessary to mount an expensive element such as a polarization beam splitter.

The inventors of the present invention performed reflection type detection on a subject having no magneto-optical response by using linearly polarized near-field light. As a result, the noise level was reduced to obtain a high-contrast optical signal. The inventors have found that reproduction is possible and have completed the present invention.

The present invention is characterized in that linearly polarized light is used as incident light to irradiate a subject through an optical probe and guide detection light to a detection element having an analyzer through the inside of the optical probe.

That is, the near-field light detection optical system of the present invention uses an optical probe having an optical aperture and a reflector covering the periphery thereof at the tip to define the resolution by the size of the optical aperture, and linearly polarized light. The beam is guided through the optical probe, the near-field light is generated from the optical aperture, is incident on the surface of the subject, and the reflected light from the subject is guided from the optical aperture to the detection element through the optical probe. The detection element is used for detection.

In the present invention, by adopting the above configuration, the reflected light (background light) from the reflector near the aperture is selectively blocked to reduce the background noise level, and the reflected light from the subject is reflected. The effect that the contrast ratio of light (signal light) can be significantly improved is obtained.

Although the present invention is effectively applied to a subject that does not exhibit a magneto-optical response, it can be similarly applied to a subject that exhibits a magneto-optical response such as a magneto-optical medium. When the present invention is applied to a subject exhibiting a magneto-optical response, in addition to the usual effect that the contrast resulting from the magneto-optical response of the subject is obtained, background light from the reflector at the tip of the optical probe is added. The effect that it can be suppressed is obtained.

The products to which the near-field optical device equipped with the near-field light detection optical system of the present invention is mainly an optical information recording / reproducing device and a near-field optical microscope. Examples of the form of the recording / reproducing apparatus include a case where the medium as the subject is a fixed type and a case where the medium is removable (removable).

When the present invention is applied to a fixed medium type recording / reproducing apparatus, a medium that does not exhibit a magneto-optical response is mainly used, but a medium that does not exhibit a magneto-optical response and a medium that exhibits a magneto-optical response are used. They may be used together, or only those exhibiting a magneto-optical response may be used.

Even when the present invention is applied to a recording / reproducing device of a medium detachable type or a near-field optical microscope, the medium or the subject may or may not exhibit a magneto-optical response. The recording / reproducing operation or the observation can be performed by the same optical system regardless of the medium or the object having any property.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

[Embodiment 1] In this embodiment, a near-field light detecting optical system mounted on the near-field optical device of the present invention is shown in FIG.
2 and FIG. 2.

FIG. 1 is a view showing the basic arrangement of the near-field light detecting optical system. In FIG. 1, 1 is a light source, 2 is a polarizer, and 3
Is a half-wave plate on the incident side, 4 is a quarter-wave plate on the incident side,
5 is a mirror, 6 is a polarization beam splitter (or a half mirror), 7 is a fiber, 8 is an optical probe, 9 is a subject, 10 is a slit, 11 is a quarter wave plate on the detection side, 12 is an analyzer, 13 Is a photodetector.

FIG. 2 is a sectional view showing the structure near the tip of the optical probe. As shown in FIG. 2, the optical probe 8
Has a structure in which an optical aperture 82 and a reflector 83 covering the periphery thereof are provided at the tip of the waveguide 81. In this embodiment,
A phase change recording medium is used as the subject 9. The subject 9 has a first interference layer 92 and a recording layer 93 on a substrate 91.
Is formed.

The light source 1 is He-in the case of a monochromatic light source.
Gas laser typified by Ne laser, Ar ion laser, Kr ion laser, or InP system, G
Semiconductor lasers such as aAs-based, GaN-based, and ZnSe-based can be used. In addition to a monochromatic light source, a white light source can be used for application to a microscope. In this embodiment,
A He-Ne laser is used as a light source.

The half-wave plate 3 on the incident side is not always necessary for the optical system of the present invention. However, as will be described later, in the present embodiment, the direction of the linearly polarized light incident on the subject is changed by inserting the ½ wavelength plate 3 in the optical path and rotating it.

The incident side quarter wave plate 4 is not used in this embodiment. That is, when the fiber 7 is a polarization plane preserving type, the quarter wavelength plate 4 is usually unnecessary. In addition, the light passing through the polarizer 2 does not pass through the fiber,
The quarter-wave plate 4 is not necessary even when converging with the lens system. However, if the polarization plane-maintaining fiber has some retardation or is not the polarization plane-maintaining fiber, the quarter wave plate 4 is used to rotate the fiber to compensate for the fiber retardation and It is preferable to adjust the light incident on the subject to be linearly polarized light. The 1/4 wavelength plate 4 is shown in FIG. 1 as will be described later, in the optical system of the comparative example
This is because the four wavelength plate 4 is inserted and rotated to circularly polarize the light emitted from the optical aperture.

Although the mirror 5 is not always necessary for the optical system of the present invention, it is used for adjusting the optical path in this embodiment. Although the fiber 7 is used in the present embodiment, a lens system may be used instead of the fiber 7 to guide the incident light to the optical probe 8 and further irradiate the subject 9.

Although the slit 10 is not always necessary for the optical system of the present invention, it is provided in this embodiment to block stray light. An appropriate lens system may be used instead of the slit 10. The quarter-wave plate 11 on the detection side is not always necessary for the optical system of the present invention, but in the present embodiment, it is provided to make the elliptically polarized component of the reflected light from the subject 9 linearly polarized and to improve the contrast ratio. ing. In the optical system of the present invention, it is essential that the photodetector 13 includes the analyzer 12. As will be described later, in the optical system of the comparative example, the quarter wave plate 11 on the detection side and the analyzer 12 are not provided.

The subject 9 may be a material that does not exhibit a magneto-optical response or a material that does not exhibit a magneto-optical response. The same optical system can be used for materials having both properties. The material that does not exhibit magneto-optical response is not particularly limited as long as it exhibits optical changes such as reflectance change, phase change, and unevenness. In this embodiment, a phase change recording medium is used as the subject 9.

The specimen used in this example was prepared according to the following procedure. First, a ZnS—SiO ₂ first interference layer, G
eSbTe recording layer, ZnS—SiO ₂ second interference layer, Al
The alloy reflective layer was sequentially formed by magnetron sputtering. The film thickness of each layer is adjusted so that an appropriate signal-to-noise ratio can be obtained during a recording / reproducing experiment, and an appropriate reflectance difference can also be obtained during mark observation with the optical system having the configuration of FIG. It was adjusted. Next, after initial crystallization of the recording layer,
The recording / reproducing test apparatus was set to form an amorphous recording mark. The mark was formed on the land so that the optical probe could be as close as possible to the mark during observation. afterwards,
The second interference layer and the reflective layer were peeled off to expose the recording layer on which the amorphous mark train was recorded. As shown in FIG. 2, the subject 9 thus manufactured has a structure in which the first interference layer 92 and the recording layer 93 are formed on the substrate 91.

The subject 9 is mounted on the subject stage of the optical system shown in FIG. The light source 1 is operated to emit the observation light. The observation light passes through the polarizer 2 to become linearly polarized light, and this linearly polarized light passes through the half-wave plate 3 and its polarization direction is controlled. In the present embodiment, the ½ wavelength plate 3 is adjusted so that the polarization direction of the linearly polarized light is parallel or perpendicular to the pregroove provided on the subject 9. In this embodiment, the quarter wave plate 4 on the incident side is not provided. The light that has passed through the polarizer 2 and the half-wave plate 3 is reflected by the mirror 5, reflected by the polarization beam splitter 6, and incident on the fiber 7. The incident light guided inside the fiber 7 is guided to the optical probe 8 provided at the tip of the fiber. The light guided to the optical probe 8 propagates through the waveguide 81, and a part of the propagated light passes through the optical aperture 82 to form an evanescent field having a size equal to the aperture diameter outside the aperture.
Since the recording layer 93 is arranged in the evanescent field in the vicinity of the optical aperture 82, propagation light (reflected light) is generated by the near field interaction, and a part of it returns to the fiber 7 through the optical aperture 82 as signal light. The signal light bears optical response information based on the difference in optical reflectance between the amorphous mark portion and the crystal portion of the recording layer 93.

On the other hand, most of the incident light propagating through the waveguide 81 of the optical probe 8 is reflected multiple times by the reflector 83 coated around the aperture, and a part or all of it is made into the fiber as background light. Return to 7. This background light becomes a noise component of the signal light.

The signal light and the background light return to the polarization beam splitter 6 through the fiber 7, pass through the polarization beam splitter 6, the slit 10 and the quarter wavelength plate 11 and enter the analyzer 12. Analyzer 1
Reference numeral 2 selectively transmits signal light and selectively blocks background light, so that the photodetector 13 can detect a signal with a high contrast ratio.

Here, in order to optimize the contrast ratio, it is preferable to set the pass axis of the analyzer 12 to be optimum. For example, the pass axis of the analyzer 12 is adjusted so that the output signal becomes minimum when the optical aperture 82 is arranged on the crystal part of the recording layer 93. On the contrary, the pass axis of the analyzer 12 may be adjusted so that the output signal becomes minimum when the optical aperture 82 is on the amorphous mark of the recording layer 93. After adjusting the pass axis of the analyzer 12 as described above, the optical probe 8 was scanned within the surface of the recording layer 93 to observe an image of a region of 10 μm □. At this time, as described above, two types of images were obtained depending on whether the polarization direction of the incident light was parallel to the groove or perpendicular to the groove.

As the optical system of the comparative example, in order to make the incident light on the subject 9 circularly polarized, a ¼ wavelength plate 4 on the incident side is inserted, and a ¼ wavelength plate 11 on the detection side and an analyzer 12 are inserted. The same configuration as that shown in FIG. In the same manner as in the above example, the optical probe 8 was scanned in the plane of the recording layer 93 to obtain an image of a region of 10 μm □.

Two types of images obtained by the optical system of the embodiment,
With respect to the image obtained by the optical system of the comparative example, the contrast ratio between the amorphous part and the crystal part was quantitatively evaluated on the image processing apparatus. As a result, each of the two types of images obtained by the optical system of the example was sharper by about 10 times than the image obtained by the optical system of the comparative example. Even when the obtained images were visually observed, the images of the example and the comparative example showed a remarkable difference. Thus, according to the present invention, by using a linearly polarized light when performing reflection type detection using a near-field light detection optical system having an optical probe coated with a reflector around the optical aperture,
Background noise can be reduced and a clear image can be obtained.

Further, two kinds of images obtained by changing the polarization direction of the incident linearly polarized light in the optical system of the embodiment were compared. When the polarization direction of the incident light was parallel to the groove, only the contrast between the mark and the space was obtained, and an image of the groove recess was not obtained. On the other hand, when the polarization direction of the incident light was perpendicular to the groove, a slight contrast was produced corresponding to the groove recess. Therefore, if you want to selectively extract only marks and spaces for observation, it is preferable to set the polarization direction parallel to the groove.If you want to observe unevenness information other than marks and spaces as well, set the polarization direction in the groove direction. It is preferable to set it vertically.

The light passing through the optical aperture 82 also contains a propagating light component, and a part of the propagating light component is reflected from the recording layer 93 and contributes to the signal light. The generation ratio of the evanescent field and the propagating light depends on the wavelength used and the optical aperture size.
Although the present invention focuses on the use of the evanescent field, the propagating light component can also be used, and the same effect can be obtained for both the evanescent field and the propagating light.

In this embodiment, the phase change recording layer was used as the subject, but the object to be observed is not particularly limited as long as it has a surface that exhibits optical changes such as reflectance change, phase change, and unevenness change.

The optical system of this embodiment can also be applied to a material in which the subject exhibits a magneto-optical response, for example, a magnetic thin film represented by a magneto-optical recording layer. A subject that exhibits a magneto-optical response can detect signal light based on the magneto-optical effect while suppressing background light from the reflector at the tip of the optical probe.

[Embodiment 2] In the present embodiment, an optical information recording / reproducing apparatus manufactured based on the knowledge obtained in Embodiment 1 will be described with reference to FIGS.

FIG. 3 is a diagram showing the structure of the optical information recording / reproducing apparatus in this embodiment. In FIG. 3, 101 is a medium (corresponding to the subject), 102 is a spindle motor, 103 is a suspension arm with a slider attached to the tip, 104 is a voice coil motor, and 105.
Is a preamplifier, 106 is a variable gain amplifier, 107 is A /
D conversion circuit, 108 is a linear equalization circuit, 109 is a data detection circuit, 110 is a decoder, 111 is a drive controller, 112 is a drive control circuit, 113 is an interface, 114 is a modulation circuit, 115 is a laser driver, 1
16 is a pickup. The basic configuration of the pickup 116 is the same as that of the optical system shown in FIG. 1 except for the fiber and the optical probe.

FIG. 4 is an enlarged view showing the structures of the medium 101 and the slider 1031. In this embodiment, a phase change recording medium is used as the medium 101. In FIG. 4, the medium 101 has a structure in which a base layer 32, a recording layer 33, and a protective layer 34 are formed on a substrate 31. On the other hand, a slider 1031 is attached to the tip of the suspension arm 103, and an optical probe 1032 is attached to the air outflow side of the slider 1031.
In addition, the suspension arm 103 has a fiber 10
33 is attached. The fiber 1033 has one end connected to the pickup 116 and the other end connected to the optical probe 1032.

FIG. 5 is a diagram showing a more detailed structural example of the optical probe of FIG. In FIG. 5, the slider 10
The optical probe 1032 attached to the tip of 31
It has an optical coupler 41, a condenser lens 42, and a waveguide section 43, and an optical aperture 45 is provided at the tip (medium facing surface) of the waveguide section 43.
And a reflector 44 that covers the periphery thereof. The fiber 1033 is connected to the optical coupler 41.

The medium 101 may be removable from the recording / reproducing apparatus (removable) or may be a fixed type such as an HDD. The medium 101 may be a material that does not exhibit a magneto-optical response or a material that does not exhibit a magneto-optical response. In addition to the phase change recording medium used in this embodiment, examples of media that do not exhibit a magneto-optical response include ROM media, dye media, and shape change recording media. The medium 101 is rotatably driven by the spindle motor 102 at a predetermined number of rotations while being mounted in the recording apparatus. The light emitted from the laser diode (LD) built in the pickup 116 is converted into linearly polarized light, then collected by the optical coupler 41 and the condenser lens 42 through the fiber 1033 and propagated through the waveguide section 43. A part of the propagating light passes through the optical aperture 45 and forms an evanescent field having a size equal to the aperture diameter outside the aperture. Since the recording layer 33 is arranged in the evanescent field, propagation light (reflected light) is generated by the near-field interaction, and a part of it returns to the fiber 1033 through the optical aperture 45 as signal light and is picked up through the fiber 1033. Be led to.

The suspension 103 is rotated by the voice coil motor 104 to guide the optical opening 45 to a predetermined position on the medium surface. The spindle motor 102 and the voice coil motor 104 are driven by the drive controller 111 via the drive control circuit 112.

The data reproducing means comprises a photodetection system and a reproduction signal processing circuit built in the pickup 116. The photodetection system built in the pickup 116 has a polarizer on the emission side and an analyzer on the detection side. The LD emission light may be guided to the fiber 1033 using a polarization beam splitter, and the detection light may be guided to the analyzer set to a predetermined pass axis through the same polarization beam splitter. The light that has passed through the analyzer enters the detector and is converted into an electrical signal.

The reproduction signal circuit has a preamplifier 105, a variable gain amplifier 106, an A / D conversion circuit 107, a linear equalization circuit 108, a data detection circuit 109, and a decoder 110. The preamplifier 105 and the variable gain amplifier 106 amplify the output signal of the photodetector. A / D conversion circuit 107
Converts the amplified signal into a digital signal that is a discrete-time quantized sample value. The linear equalization circuit 108 is a kind of digital filter. Data detection circuit 109
Is a signal processing circuit for estimating data by a maximum rewrite (ML) that detects data from a reproduction signal waveform equalized by, for example, a partial response (PR), and is specifically composed of a Viterbi decoder. The decoder 110 restores the code bit string detected by the data detection circuit 109 to the original recording data.

The data recording means comprises a modulation circuit 114, a laser driver 115 and a pickup 116. The modulation circuit 114 executes an encoding process for converting the recording data sent from the drive controller 111 into a predetermined code bit string. The laser driver 115 records the mark according to the code bit string output from the modulation circuit 114 on the medium 101 so as to record the mark on the medium 101.
To drive. The data recording means does not necessarily have to be provided, and may be an apparatus having only the data reproducing means, that is, an optical reproducing apparatus.

The drive controller 111 is a main control system of the recording / reproducing apparatus, is connected to, for example, a personal computer or AV equipment via the interface 113, and controls the transfer of recording / reproducing data. Although not shown in FIG. 3, a moving picture compression circuit, a moving picture decompression circuit, and a data detection circuit 10 are used to record and reproduce video information.
An error detection / correction circuit for performing an error correction process on the data demodulated by 9 is also included. When the medium 101 is recordable and erasable, the formation of the erasing light for erasing the recorded data is executed in the modulation circuit 114, for example. In the case of a phase change recording medium, as a signal for erasing data, erasing light having an erasing power level lower than the recording power level is generated in a DC or pulse manner.

Next, the structure and manufacturing method of the medium 101 shown in FIG. 4 will be described. The substrate 31 of the medium 101 is, for example, a polycarbonate disk provided with a pregroove for a tracking guide. This disc is manufactured through a series of processes such as mastering of the master, generation of stamper plating, and injection molding. From the viewpoint of high density recording, it is preferable that the groove pitch is about the optical aperture. For this purpose, a light source with a wavelength as short as possible is used during mastering of the master, or electron beam mastering is applied. In this embodiment, the wavelength 26
A mastering machine having a 6 nm harmonic laser and an NA: 0.9 objective lens was used in combination with super-resolution using a thermobleaching dye, and the groove pitch was set to 200 nm. As the substrate, a hard substrate having a groove formed on a photopolymer, such as glass, Si wafer, or NiP-coated Al plate may be used.

The base layer 32 and the recording layer 3 are formed on the substrate 31.
3 and the protective layer 34 are sequentially formed by the magnetron sputtering method. The underlayer 32 is not necessarily provided, but an optical enhancement effect for returning the reproduction light to the reproducing system by multiple interference of the propagating light passing through the recording layer 33.
When a resin substrate is used, it is provided for the purpose of functions such as thermal insulation between the recording layer and the substrate which become high in temperature during recording, control of crystal orientation of the crystalline recording layer, and control of crystallization speed. As the recording layer, TeO, a phase change recording layer of a rewritable type represented by GeSbTe, AgInSbTe, or the like, is used.
Examples include a single-recording type phase change or diffusion double-layer recording layer represented by _x , PdTeO _x , GeTe, GeTe / BiTe bilayer film, and a dye-based recording layer represented by phthalocyanine. In the case of a ROM medium in which information is previously recorded in the form of a pit train on the substrate, the reflective film provided on the substrate functions as a recording layer. Protective layer 34
Has a function of mechanically protecting the recording layer when performing a proximity operation, a smooth high-speed movement of the slider, and an anti-oxidation function of the recording layer. When the slider operation is performed as in the present embodiment, it is preferable to use the carbon film and the lubricating layer in combination as in the HDD medium.

In this embodiment, as the underlayer, 100 nm thick ZnS-SiO ₂ or 100 nm thick Al / 100 is used.
20 nm as a recording layer for a ZnS-SiO ₂ bilayer underlayer having a thickness of nm
nm GeSbTe phase change recording layer, 5n as protective layer
m-thick carbon was used. A perfluorocarbon-based lubricating layer was applied on the protective layer by a dip method. After forming the medium,
The recording layer was initially crystallized.

Next, the structure and manufacturing method of the optical probe shown in FIG. 5 will be described. The slider 10 is attached to the tip of the suspension 103 via a gimbal portion or a piezoelectric element.
31 is attached. The fiber 1033 is fixed by the claws of the suspension 103, and the slider 103
It is connected to the optical probe 1032 on the air outflow side of 1. It is preferable to use a polarization-preserving type fiber as the fiber 1033. Alternatively, the light may be condensed using a lens system without using the fiber 1033. Optical probe 1
032 receives the light from the fiber 1033 by the optical coupler 41, and the condenser lens 42 condenses and irradiates the waveguide 43. The lens may be a normal objective lens, but may be a holographic lens or a grating lens. In order to reduce the weight of the optical probe 1032 and enable high-speed seek operation of the suspension, it is preferable to use an optical element that is as small and lightweight as possible. Most preferably, a thin-film grating lens is placed close to the fiber output end except for the coupler, and the waveguide 43 and the reflector 44 are manufactured by a thin-film process. In that case, it is preferable that a thin film lens, a waveguide portion made of a transparent body, and a reflector are formed on a thin film substrate in a thin film process, a fiber insertion hole is formed from the back surface of the substrate, chipping is performed, and then the slider is attached to a slider. From the viewpoint of processing and mechanical characteristics, it is preferable to use AlTiC as the material of the slider, as in the case of the head for HDD.
The transparent material forming the waveguide portion 43 can be selected from a wide range of material systems such as metal oxides, nitrides, borides, carbides, and fluorides. As the reflector 44, metal or T
A metal compound represented by iN or the like is used. The optical aperture 45 is formed by the PEP process or the FIB process. In this embodiment, the diameter of the optical aperture 45 is 150 nm.

Using the optical information recording / reproducing apparatus having the above-described structure, recording / reproducing of the phase change recording medium was performed as follows. To clarify the effect of the invention, in addition to the configuration of FIG. 3, a spectrum analyzer is attached to the output part of the preamplifier and a bit error rate (BER) measuring instrument is attached to the output side of the data detection circuit.

After the medium 101 is mounted on the spindle motor 102, the medium 101 is rotated and the pickup 11
Focusing and tracking were performed by irradiating the light of the reproduction power level from No. 6. Focusing and tracking means are similar to those of an ordinary optical recording / reproducing apparatus, but the optical probe 1 is also used for focusing and tracking signals.
Since the background light from the 032 tip reflector 44 is superimposed, it is preferred according to the invention to acquire the signal through the analyzer using linearly polarized light.

Next, from the personal computer, the interface 11
A test signal of a single frequency is input as a recording signal via the control circuit 3, and the modulation circuit 114 and the LD driver 115 are operated in accordance with a command from the drive controller 111 to generate a recording pulse light from the LD light source built in the pickup 116. Emitted. Although it is not necessary to use a polarizer originally during recording, the recording / reproducing apparatus of this embodiment also uses a polarizer during recording. Inside the pickup 116, the recording light is a polarizer, a half-wave plate provided if necessary, an appropriate condenser lens system, a polarization beam splitter,
It is input to the fiber 1033 through the coupler. The light propagated through the fiber 1033 is reflected by the optical probe 1032.
To the surface of the medium 101 through the optical aperture 45.
Since the total thickness of the carbon protective layer 34 and the lubricating layer is about 10 nm, if the flying height of the slider 1031 is several tens nm, the recording layer can be arranged in the near field generated near the optical aperture 45. Similar to a normal phase change recording / reproducing apparatus, an amorphous recording mark is formed in a portion irradiated with a recording level of light, and the other portion becomes a crystal space. By controlling the frequency of the reference signal and the medium linear velocity, an amorphous mark row having a length of 200 nm was recorded in the track direction with a crystal space having a length of 200 nm interposed therebetween. The recorded mark row was reproduced by irradiating light of a reproduction power level in a DC manner. In the present invention, linearly polarized light is used as the reproduction light, and the detection system is provided with an analyzer. The reproduced CNR of the reference signal detected according to the present invention was 52 dB, which was a practical value. In addition, after randomly recording a random pattern signal on five tracks on the medium by overwriting 1000 times,
Was measured. As a result, the BER was 10E-5 or less on any track, which was a sufficiently practical value. Finally, when a moving image was input, recorded, and reproduced, a clear image without distortion or defects could be obtained.

On the other hand, for comparison, the structure of the pickup is changed to remove the analyzer from the detection system by providing a ¼ wavelength plate on the incident side in the same manner as described in the first embodiment. A recording / reproducing device of a comparative example using circularly polarized light as incident light was manufactured. Recording / reproducing was performed in the same manner as above using the recording / reproducing apparatus of the comparative example. As a result, the playback CNR is 40d.
Below B, the BER showed a low value of 10E-2 to 10E-3. In addition, the reproduction of the moving image could not be performed at all.

In this embodiment, the phase change medium is used as the medium, and the medium is removable from the apparatus. As the medium, in addition to the phase change medium, a shape change type, a pigment type, a ROM, etc. can be freely mounted. In addition, in the removable recording / reproducing apparatus, not only a medium that does not exhibit a magneto-optical response but also a medium that exhibits a magneto-optical response, typically a magneto-optical recording medium, may be mounted for recording / reproduction or reproduction. it can. When the present invention is applied to a magneto-optical recording medium, it is possible to significantly suppress the background noise caused by the reflector at the tip of the optical probe and perform the reproduction utilizing the magneto-optical effect. This effect is also obtained for focusing and tracking.

The medium may be fixed to the device and used as in the HDD. In this case, as the medium, only those which do not exhibit a magneto-optical response may be used, those which do not exhibit a magneto-optical response and those which exhibit a magneto-optical response may be used together, and only those which exhibit a magneto-optical response. May be used.

[Embodiment 3] In this embodiment, a near-field optical microscope will be described with reference to FIG. FIG. 6 is a diagram showing the configuration of the near-field optical microscope of this embodiment.

In FIG. 6, 501 is an observation light source, and 50
2 is a polarizer, 503 is an incident side half-wave plate, 504 is an incident side quarter-wave plate, 505 is a beam splitter, 50
6 is a fiber coupler, 507 is a fiber, 508 is a reflector, 509 is an optical aperture, 510 is an object, 511 is a detection side quarter-wave plate, 512 is an analyzer, 513 is an avalanche photodiode (APD), 514 is A photon counter, 515 is a computer, 516 is a monitor, 517 is a semiconductor laser, 518 is a photodetector, 51
9 is a lock-in amplifier, 520 is a piezo element, 521 is a piezo stage, 522 is a stage controller, 52
3 is a shear force controller.

The tip of the fiber 507 is processed into a two-step tapered shape by chemical etching, and a 200 nm-thick Au film is sputter-coated on the tapered portion as a reflector 508. Then, the tip is pressed against a flat surface to form an optical opening 509. did. The optical aperture has a diameter of 15n according to electron microscope observation.
m was confirmed. In this embodiment, fiber 5
The tapered portion of the tip of 07 functions as an optical probe provided with the optical aperture 509 and the reflector 508 that covers the periphery thereof. By setting this fiber 507, the near-field optical microscope of FIG. 6 was produced. A lens system may be used instead of the fiber 507.

As the light source 501, the various light sources described in the first embodiment such as a He-Ne laser can be adopted, and a white light source such as a Xe lamp can also be used. In this embodiment, a He—Ne laser is used as the light source 501.

The half-wave plate 503 on the incident side is not always necessary for the microscope of the present invention. However, as will be described later, in the present embodiment, the half-wave plate 503 is inserted in the optical path and is rotated to change the direction of the linearly polarized light incident on the subject.

The quarter wave plate 504 on the incident side is not used in this embodiment. That is, when the fiber 507 is a polarization plane preserving type, the quarter wavelength plate 504 is usually unnecessary. However, even if the polarization plane preserving fiber has some retardation or is not the polarization plane preserving fiber, it is rotated by using the ¼ wavelength plate 504 to compensate the retardation of the fiber,
It is preferable to adjust the light entering the subject through the optical aperture to be linearly polarized light. FIG. 6 shows a quarter wave plate 504.
The reason is that, as will be described later, in the microscope of the comparative example, the quarter wave plate 504 is inserted in the optical path, and the light emitted from the optical aperture is circularly polarized by rotating this. .

The quarter-wave plate 511 on the detection side is not always necessary for the microscope of the present invention, but in the present embodiment, the subject 5
It is provided in order to make the elliptically polarized component of the reflected light from 10 linearly polarized and improve the contrast ratio. In the microscope of the present invention, it is essential that the photodetector includes the analyzer 512. As will be described later, in the microscope of the comparative example, the quarter wave plate 511 on the detection side and the analyzer 512 are not provided.

Although the photon counter 514 is used in the detection system in this embodiment, a chopper is provided between the light source 501 and the polarizer 502, and the output of the APD 513 is differentially amplified by the lock-in amplifier 519, and the computer 5
You may enter in 15.

The object 510 may be a material that does not exhibit a magneto-optical response or a material that does not exhibit a magneto-optical response. The same optical system can be used for materials having both properties. The material that does not exhibit magneto-optical response is not particularly limited as long as it exhibits optical changes such as reflectance change, phase change, and unevenness. In this embodiment, a phase change recording medium is used as the subject 510. The test object 510 was manufactured in the same procedure as in Example 1.

A procedure for observing a subject using the near-field optical microscope of this embodiment will be described. The subject 510 is attached to the piezo stage 521. The light source 501 is operated to emit observation light. The observation light becomes linearly polarized light through the polarizer 502, and this linearly polarized light passes through the half-wave plate 503 and its polarization direction is controlled. In this embodiment, the half-wave plate 50 is arranged so that the polarization direction of the linearly polarized light is parallel or perpendicular to the pre-groove provided on the subject 510.
Adjusting 3. In this embodiment, the quarter wave plate 504 on the incident side is not provided. It passes through a polarizer 502 and a half-wave plate 503, and a beam splitter 505.
The light that has passed through is incident on the fiber 507 through the fiber coupler 506. The light guided through the fiber 507 is guided to an optical probe (a taper portion provided with an optical aperture 509 and a reflector 508) provided at the tip of the fiber 507. A part of the light guided to the optical probe passes through the optical aperture 509 and forms an evanescent field having a size equivalent to the aperture diameter outside the aperture. Since the subject 510 is placed in the evanescent field near the optical aperture 509, propagation light (reflected light) is generated by near-field interaction,
A part of it returns to the fiber 507 through the optical aperture 509 as signal light. The signal light bears optical response information based on the difference in optical reflectance between the amorphous mark portion and the crystal portion of the recording layer of the object 510.

On the other hand, most of the light incident on the fiber 507 is reflected multiple times by the reflector 508 coated around the optical aperture 509, and part or all of the light returns to the fiber 507 as background light. This background light becomes a noise component of the signal light.

The signal light and the background light are reflected by the beam splitter 505 through the fiber 507, pass through the quarter-wave plate 511, and enter the analyzer 512. Since the analyzer 512 selectively transmits the signal light and selectively blocks the background light, the APD 513
Can detect signals with high contrast ratio. Here, in optimizing the contrast ratio, it is preferable to optimally set the pass axis of the analyzer 512. For example, the pass axis of the analyzer 512 is adjusted so that the output signal becomes minimum when the optical aperture 509 is arranged on the crystal part of the recording layer. vice versa,
The pass axis may be adjusted so that the output signal is minimized when the optical aperture 509 is on the amorphous mark.

The signal light passing through the analyzer 512 is APD5.
Amplified by 13, and converted into an electric signal pulse by a photon counter 514. This signal pulse is input to a computer 515 as a control system, subjected to appropriate processing, and then displayed as an image on a monitor 516 including a display, a printer and the like.

Next, the position control system for the object and the optical probe in the microscope of this embodiment will be described. The position control system includes a laser 517, a photodetector 518, a lock-in amplifier 519, a shear force controller 523, a stage controller 522, and a piezo stage 521.

The local oscillator incorporated in the lock-in amplifier 519 vibrates the piezo element 520 for vibrating the fiber, and the tip of the fiber vibrated by the vibration is irradiated with the emitted light of the laser 517, and the reflected light is detected. It is detected at 518. The output of the detector 518 is amplified by the lock-in amplifier 519, and the shear force controller 52
Input to 3. The shear force controller 523
The piezo stage 5 is connected via the stage controller 522 so that the signal amplification obtained from the detector 518 becomes constant.
21 is driven to control the distance between the tip of the fiber 507 and the subject 510. The stage controller 522 and the piezo stage 521 also control the position of the subject 510.
Examples of the position control means include an optical lever method and a shear force feedback method in which a piezo element detects vibration by vibrating with a tuning fork, in addition to the above-described sheer force feedback method in which light is detected.

By the above operation, an image of a 10 μm square area on the surface of the object 510 was observed. At this time, as described above, two types of images were obtained depending on whether the polarization direction of the incident light was parallel to the groove or perpendicular to the groove.

As the microscope of the comparative example, in order to make the incident light on the object 510 circularly polarized, the quarter wavelength plate 50 on the incident side is used.
4 is inserted, the angle is adjusted, and the quarter wave plate 511 on the detection side is inserted.
The same configuration as that of FIG. 6 was used except that the analyzer 512 was omitted. An image of a region of 10 μm □ on the surface of the subject 510 was obtained in the same manner as in the above example.

Two kinds of images obtained by the microscope of the embodiment,
When the images obtained by the microscope of the comparative example were compared on the monitor 516, the two types of images of the examples had a very high contrast and a sharp contrast, while the images of the comparative example showed amorphous marks and crystals. The boundary area of the part was blurred and unclear. The contrast ratio between the amorphous part and the crystal part was quantitatively evaluated on the image processing apparatus. As a result, both of the two types of images obtained by the microscope of the example had a contrast ratio 10 times or more higher than that of the image obtained by the microscope of the comparative example. Thus, according to the present invention, by using linearly polarized light when performing reflective detection using a near-field optical microscope having an optical probe coated with a reflector around the optical aperture, background noise is reduced and sharpened. You can get a good image.

Further, two types of images obtained by changing the polarization direction of the incident linearly polarized light with the microscope of the embodiment were compared. When the polarization direction of the incident light was parallel to the groove, only the contrast between the mark and the space was obtained, and an image of the groove recess was not obtained. On the other hand, when the polarization direction of the incident light was perpendicular to the groove, a slight contrast was produced corresponding to the groove recess. Therefore, if you want to selectively extract only marks and spaces for observation, it is preferable to set the polarization direction parallel to the groove.If you want to observe unevenness information other than marks and spaces as well, set the polarization direction in the groove direction. It is preferable to set it vertically.

The light that has passed through the optical aperture 509 also contains a propagating light component, and a part of the propagating light component is reflected from the recording layer and contributes to the signal light. The generation ratio of the evanescent field and the propagating light depends on the wavelength used and the optical aperture size. Although the present invention focuses on the use of the evanescent field, the propagating light component can also be used, and the same effect can be obtained for both the evanescent field and the propagating light.

In this embodiment, the phase change recording layer was used as the subject, but the object to be observed is not particularly limited as long as it has a surface that exhibits optical changes such as reflectance change, phase change, and unevenness change.

The microscope of this embodiment can also be applied to the observation of a material whose specimen exhibits a magneto-optical response, for example, a magnetic thin film represented by a magneto-optical recording layer. An object that exhibits a magneto-optical response can be observed based on the magneto-optical effect while suppressing the background light from the reflector at the tip of the optical probe.

[0089]

As described in detail above, according to the present invention, in the reflection detection type near-field optical device having good resolution, the background light from the reflector provided around the optical aperture at the tip of the optical probe is provided. The noise caused by can be significantly reduced. Therefore, in the field of optical recording / reproducing devices,
A significant improvement in recording density is expected. Further, in the field of near-field optical microscope, the resolution can be greatly improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a near-field light detection optical system according to the present invention.

FIG. 2 is a cross-sectional view showing an optical probe and a subject used in the optical system of FIG.

FIG. 3 is a diagram showing a configuration of an optical information recording / reproducing apparatus according to the present invention.

4 is a cross-sectional view showing a slider and a medium mounted on the recording / reproducing apparatus of FIG.

5 is a sectional view showing an optical probe used in the recording / reproducing apparatus of FIG.

FIG. 6 is a diagram showing a configuration of a near-field optical microscope according to the present invention.

[Explanation of symbols]

1 ... Light source 2 ... Polarizer 3 ... Incident side half-wave plate 4 ... Incident side quarter wave plate 5 ... Mirror 6 ... Polarizing beam splitter 7 ... Fiber 8 ... Optical probe 9 ... Subject 10 ... Slit 11 ... Detection side quarter wave plate 12 ... Analyzer 13 ... Photodetector 31 ... Substrate 32 ... Underlayer 33 ... Recording layer 34 ... Protective layer 41 ... Optical coupler 42 ... Condenser lens 43 ... Waveguide 44 ... Reflector 45 ... Optical aperture 81 ... Waveguide 82 ... Optical aperture 83 ... Reflector 91 ... Substrate 92 ... First interference layer 93 ... Recording layer 101 ... Medium 102 ... Spindle motor 103 ... Suspension arm 104 ... Voice coil motor 105 ... Preamplifier 106 ... Variable gain amplifier 107 ... A / D conversion circuit 108 ... Linear equalization circuit 109 ... Data detection circuit 110 ... Decoder 111 ... Drive controller 112 ... Drive control circuit 113 ... Interface 114 ... Modulation circuit 115 ... Laser driver 116 ... Pickup 501 ... Observation light source 502 ... Polarizer 503 ... Half wave plate on incident side 504 ... Incident side quarter-wave plate 505 ... Beam splitter 506 ... Fiber coupler 507 ... Fiber 508 ... Reflector 509 ... Optical aperture 510 ... Subject 511 ... Detection side quarter-wave plate 512 ... Analyzer 513 ... Avalanche photodiode (APD) 514 ... Photon counter 515 ... Computer 516 ... Monitor 517 ... Semiconductor laser 518 ... Photodetector 519 ... Lock-in amplifier 520 ... Piezo element 521 ... Piezo stage 522 ... Stage controller 523 ... Shea force controller 1031 ... slider 1032 ... Optical probe 1033 ... Fiber

Continuation of front page (51) Int.Cl. ⁷ Identification code FI G11B 11/105 551 G11B 11/105 551A 566 566C (72) Inventor Keiichiro Yusu 1 Komukai Toshiba Town, Kawasaki City, Kanagawa Prefecture Toshiba Research Co., Ltd. (72) Inventor Toshiharu Saiki 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa Kanagawa Academy of Science and Technology (72) Inventor Toshiyasu Tadokoro, Ishikawacho, Hachioji, Tokyo 2967-5 Nihonbunko stock In-house (56) Reference JP 7-254185 (JP, A) JP 10-269614 (JP, A) JP 4-291310 (JP, A) JP 2000-163794 (JP, A) JP-A-9-293288 (JP, A) JP-A-2001-13154 (JP, A) JP-A-10-221353 (JP, A) JP-A-2000-173071 (JP, A) JP-A-10-325840 (JP , A) JP-A-11-305135 (JP, A) JP-B-6-75311 (JP, B2) Patent 2822280 (JP, B2) T.S. Saiki and K.K. Matsuda, Near-field optical fiber probe optimized illumi- nation-collection hybrid mode operation, October, 1999, Applied Physics Letters, October, USA. p.2773-2775 (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01N 13/10-13/24 G02B 21/00 G11B ^7/ 12-7/22 G11B 11/105-11/26 G12B 21/00-21/24 JISST file (JOIS)

Claims (5)

(57) [Claims] 1. A light source, means for generating linearly polarized light from the light emitted from the light source, and a structure provided with an optical aperture and a reflector for covering the periphery of the optical aperture at the tip, and the linearly polarized light is guided. An optical probe that oscillates to generate near-field light from the optical aperture and enters the subject surface, and guides reflected light from the subject through the optical aperture; and an optical probe. And a detection element for detecting reflected light passing through the analyzer through the analyzer, wherein the analyzer is from a reflector near the optical aperture.
Selectively block reflected background light
A near-field light detection optical system characterized by being adjusted to . 2. A light source, means for generating linearly polarized light from the light emitted from the light source, and a structure provided with an optical aperture and a reflector covering the periphery of the optical aperture at the tip, and the linearly polarized light is guided. An optical probe that oscillates to generate near-field light from the optical aperture and enters the subject surface, and guides reflected light from the subject through the optical aperture; and an optical probe. And a detection element for detecting reflected light passing through the analyzer through the analyzer, wherein the analyzer is from a reflector near the optical aperture.
Selectively block reflected background light
Near-field optical device characterized by being adjusted to . 3. A light source, means for generating linearly polarized light from the light emitted from the light source, and a structure provided with an optical aperture and a reflector covering the periphery thereof at the tip, and the linearly polarized light is guided. An optical probe that oscillates to generate near-field light from the optical aperture and enters the subject surface, and guides reflected light from the subject through the optical aperture; and an optical probe. And a detection element for detecting reflected light passing through the analyzer through the analyzer, wherein the analyzer is from a reflector near the optical aperture.
Selectively block reflected background light
A near-field optical microscope characterized by being adjusted to . 4. A light source and means for generating linearly polarized light from the light emitted from said light source.
And a reflector is provided at the tip to cover the optical aperture and its surroundings.
Has a structure that guides the linearly polarized light through the optical aperture.
Generates near-field light from the medium and makes it enter the medium surface.
An optical probe that guides light reflected from the body through the optical aperture.
It has a lobe and an analyzer, and it reflects the reflected light that has passed through the optical probe.
And a detecting element for detecting through the analyzer , wherein the analyzer is a reflector near the optical aperture.
Selectively block reflected background light
Optical information reproducing device characterized by being adjusted to
Place 5. A reflection having an optical aperture at the tip and covering the periphery thereof.
Using an optical probe having a structure provided with a body,
Guide the linearly polarized light to the optical probe and get close to the optical aperture.
Generates field light and makes it incident on the surface of the subject, and
The reflected light from the body is passed through the optical aperture to the optical probe.
It is guided by the detector and is detected by the detector through the analyzer.
Before detecting the optical information on the surface of the sample by
The analyzer is reflected from the reflector near the optical aperture.
Adjust to selectively block background light
A method for detecting optical information, characterized in that