JPH095047A - Mode interference type laser scanning microscope - Google Patents

Abstract

PURPOSE: To provide a mode interference type laser scanning microscope by which illumination light is propagated only in 0-order mode in a waveguide and a luminous spot symmetric to center point can be projected to an object to be inspected. CONSTITUTION: Light emitted out of a light source 102 is propagated in the TM mode successively through a branch waveguide path 105 and a main waveguide path 125 and projected to an object 111 to be inspected from the end face of the main waveguide 125. Reflected light from the object 111 to be inspected is led to the end face of the main waveguide 125, propagated in the TE mode successively through the main waveguide 125 and branch waveguide 106, 107 on both sides, and detected by detectors 103, 104. The main waveguide 125 is made as to be a charged single mode waveugide by a metal film 115 for the light in the TM mode and be a double mode waveguide for the light in the TM mode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mode interference type laser scanning microscope for detecting a step or reflectance distribution of an object by utilizing interference between modes in an optical waveguide.

[0002]

2. Description of the Related Art In recent years, optical waveguides have attracted attention in the fields of optical communication and optical measurement. The reason is that the use of the optical waveguide has the advantages that the optical system can be made smaller and lighter, and the adjustment of the optical axis becomes unnecessary.

As one of measuring instruments utilizing an optical waveguide,
Mode interference laser scanning microscopes are known. A mode interference type laser scanning microscope is disclosed in, for example, Japanese Patent Laid-Open No. 4-208.
No. 913.

The structure of the mode interference laser scanning microscope will be briefly described with reference to FIG.

As shown in FIG. 3, the mode interference type laser scanning microscope focuses a laser beam on an object 11 to be inspected by a focusing optical system 10. Condensing optical system 10 for this laser spot
A channel waveguide is provided at the spot image position of The channel waveguide is a double-mode waveguide 8 having an end face at the spot image position, and three single-mode waveguides 5 from the double-mode waveguide 8 by a branch portion 15.
6 and 7. A light source 2 for irradiating the object 11 with light is arranged at the end face of one single-mode waveguide 5 in the center of the three single-mode waveguides, and two single-mode waveguides on both sides are arranged. Detectors 3 and 4 for detecting the amount of guided light are arranged on the end faces of the mode waveguides 6 and 7. The center line of the single single-mode waveguide 5 at the center is arranged so as to coincide with the center line of the double-mode waveguide 8.

The illumination light emitted from the light source 2 propagates through the central single-mode waveguide 5, further propagates through the double-mode waveguide 8, and is emitted from the end face of the double-mode waveguide 8 to the object 11 to be inspected. Is irradiated. Since the centerline of the central single-mode waveguide 5 and the centerline of the double-mode waveguide 8 are in the same positional relationship, the light incident on the double-mode waveguide 8 from the central single-mode waveguide 5 is , Only the 0th mode is excited in the double mode waveguide 8. Therefore, from the end face of the double mode waveguide 8,
Spot light having a normal distribution of light intensity and phase is emitted to the object 11 to be inspected.

If the object 11 to be inspected has an inclination or a step, a phase distribution is generated in the light spot of the reflected light, and the object 1 to be inspected 1
When there is a reflectance distribution at 1, an intensity distribution occurs in the light spot of the reflected light, and the light spot becomes asymmetric in each case.

The reflected light from the object 11 to be inspected enters from the end face of the double mode waveguide 8 and propagates through the double mode waveguide 8. At this time, when the light spot has asymmetry, both zero-order and first-order mode lights are excited in the double-mode waveguide 8, and both modes propagate in the double-mode waveguide 8 while interfering with each other. And branching part 15
Then, it branches into two channel waveguides 6 and 7 on both sides. 0
Since the interference light between the second-mode light and the first-mode light is asymmetric in the double-mode waveguide 8, the light amounts propagating through the two channel waveguides 6 and 7 are detected by the detectors 3 and 4, respectively.
And the difference between the two is detected by the differential amplifier 12, the microscopic inclination of the object to be inspected, step information, and reflectance distribution information are detected.

[0009]

As described above, in the mode interference type laser scanning microscope disclosed in Japanese Unexamined Patent Publication No. 4-208913, the center line of the central single mode waveguide and the double mode waveguide are formed. Match the center line,
Moreover, by configuring the branching region so as to have a symmetrical shape across the center line, the light incident from the single mode waveguide in the center to the double mode waveguide is zero-ordered in the double mode waveguide. It propagates only in mode.

However, since the widths of the single mode waveguide and the double mode waveguide are as very small as several μm, it is difficult in the manufacturing process to make their center lines completely coincide with each other. Further, the branch region portion has a fine and complicated shape because the waveguide having a width of several μm is branched into three. Therefore, it is difficult in the manufacturing process to form the branch region portion so as to be completely symmetrical with respect to the center line.

Therefore, in the conventional mode interference type laser scanning microscope, in the manufacturing process, the center line of the waveguide is deviated, the branch region portion is not center symmetric but asymmetric, and the refractive index of the double mode waveguide is large. When the light enters the double mode waveguide from the single mode waveguide in the center, the phenomenon in which the first mode is excited in addition to the 0th mode occurs due to the uneven distribution.

When the first-order mode is excited, the light spot emitted from the end face of the double mode waveguide and irradiated on the object to be inspected is not a normal distribution of the light intensity or phase, but becomes asymmetric. I will end up. The mode interference laser scanning microscope of FIG. 3 detects the asymmetry of the test object as the asymmetry of the reflected light. Therefore, if the illumination light to the test object is asymmetric, the There is a problem that the microscopic inclination of the object to be inspected cannot be detected accurately.

It is an object of the present invention to provide a mode interference type laser scanning microscope capable of propagating illumination light in a waveguide only in the 0th mode and irradiating a symmetrical light spot on an object to be inspected.

[0014]

In order to achieve the above object, according to the present invention, an illuminating unit for irradiating an object to be inspected with light and a detection for detecting reflected light from the object to be inspected. Section and a waveguide section, and the waveguide section includes a main waveguide, a branch section for branching the main waveguide into three waveguides, and three branch waveguides connected to the branch section. And the illumination unit is arranged so that light is incident on a central branch waveguide of the three branch waveguides, and the detection unit is arranged among the three branch waveguides. The waveguide section is arranged so as to detect the light propagated through the branch waveguides on both sides, and the waveguide section propagates the light irradiated by the illuminating section in the order of the branch waveguide, the branch section, and the main waveguide, and thus the main waveguide. Exits from the end face of the object to be inspected, the reflected light from the object to be injected from the end face, the main waveguide,
The branch section and the branch waveguide are arranged so as to propagate in this order to be guided to the detection section. At least a part of the main waveguide is a loading type, and the loading section of the main waveguide is TE.
A mode interference type laser scanning microscope is provided which is a double mode waveguide for one of mode light and TM mode light and a single mode waveguide for the other.

[0015]

The light emitted from the illumination section propagates through the central branch waveguide and enters the main waveguide connected to the branch section.
Light that has entered the main waveguide from the central branch waveguide propagates in the main waveguide in the 0th mode. Since the 0th-order mode light is light having a centrally symmetric distribution, a centrally symmetric light beam is emitted from the end surface of the main waveguide toward the object to be measured.

When the object to be inspected has an inclination or a step or the reflectance is distributed, the reflected light from the object to be inspected becomes asymmetric. When the reflected light has asymmetry, when the reflected light enters from the end face of the main waveguide, when the main waveguide is a double-mode waveguide, both 0th-order and 1st-order mode light are excited. . The 0th-order mode light and the 1st-order mode light propagate through the main waveguide while interfering with each other, reach the branching region, branch into two branch waveguides on both sides, and are detected by the detection unit. Two
By detecting the difference in the light amount of the branch waveguides, the microscopic inclination of the object to be inspected, step information, and reflectance distribution information are detected.

In the present invention, by loading the main waveguide, the equivalent refractive index of the TM mode light and the equivalent refractive index of the TE mode light are set to different values, and the TM mode light and the T mode light are transmitted.
A single mode waveguide is used for one of the E mode lights and a double mode waveguide is used for the other. The light from the illumination unit propagates in the mode of the single mode waveguide of the TM mode light and the TE mode light, and the reflected light from the test object is the TM mode light and the TE mode light. Of these, the main waveguide propagates in the mode of the double mode waveguide.

As a result, even if the center line of the central branch waveguide and the center line of the main waveguide are not completely coincident with each other, the primary mode is excited in the main waveguide by the light from the illumination unit. Therefore, the main waveguide can always irradiate the object to be inspected with the centrosymmetric light beam propagated in the 0th mode.

[0019]

An embodiment of the present invention will be described with reference to the drawings.

First, the structure of the mode interference type laser scanning microscope of this embodiment will be described with reference to FIG.

As shown in FIG. 1, the mode interference type laser scanning microscope of this embodiment has a laser light source 102 and a detector 1.
It has the optical waveguide substrate 101 to which 03 and 104 are attached. The optical waveguide substrate 101 includes a main waveguide 12
5, branch portion 108, and three branch waveguides 105, 106, and 107 connected to branch portion 108 are formed.

The light source 102 comprises three branch waveguides 105, 1
It is attached to the end face of the central branch waveguide 105 of 06 and 107. The detectors 103 and 104 are attached to the end faces of the branch waveguides 106 and 107 on both sides of the three branch waveguides 105, 106 and 107, respectively.

The light source 102 emits linearly polarized light in the TM mode direction of the branch waveguide 105. Central branch waveguide 105
Is a single mode buried waveguide for the TM mode.

The branch waveguides 106 and 107 on both sides are
It is a single mode buried waveguide for the TE mode. The detectors 103 and 104 are arranged so that TE mode light can be detected.

The main waveguide 125 is a buried type waveguide for TE mode light, but is a loaded type waveguide loaded with a metal film 115 for TM mode light. Specifically, by loading a pair of metal films 115 on the double-mode buried waveguide for TE mode light, the equivalent refractive index of TM mode light is lowered, and for TM mode light, This is a configuration that acts as a single mode waveguide. The pair of metal films 115 are symmetrically arranged with the center line of the buried waveguide interposed therebetween.

In this embodiment, an X-cut Y-propagating LiNbO ₃ substrate is used as the substrate 101, and a buried waveguide is formed by diffusion of Ti. The widths of the buried waveguides are about 4 μm for the branch waveguides 105, 106 and 107 and about 8 μm for the main waveguide 125. The metal film 115 is made of Al
It is formed by.

The interval between the pair of metal films 115 is formed in advance by the calculation so that the TM zero-order mode light is not cut off, but the TM first-order mode light is cut off.

The optical waveguide substrate 101 is a main waveguide 125.
Are arranged so that the light emitted from the end surface of the object is irradiated to the object 111 to be inspected.

The end face of the main waveguide 125 and the object to be measured 111
A quarter-wave plate 121, an XY two-dimensional scanning device 122, and a condenser lens 110 are sequentially arranged on the optical path of. The quarter-wave plate 121 is the main waveguide 1
The 25 polarization modes are arranged so as to convert the linearly polarized light in the TM mode light direction into circularly polarized light.

Further, a differential amplifier 112 for outputting the difference between these outputs is connected to the detectors 103, 104. The differential amplifier 112 and the scanning device 122 are
It is connected to the control device 113. The control device 113 is
It is connected to the display device 114.

Next, the operation of the mode interference type laser scanning microscope of FIG. 1 will be described.

The light emitted from the light source 102 propagates in the single mode waveguide 105 in the TM mode, and the branch portion 1
The light passes through 08 and enters the main waveguide 125. At this time, if the shape of the branching portion 108 is slightly asymmetrical, if the main waveguide 125 is a double mode,
Not only the 0th-order mode but also the 1st-order mode is excited. However, as described above, in the present embodiment, the main waveguide 125 is a single-mode waveguide for the TM mode light by loading the metal film 115. It propagates through 125 and is emitted from the end face. As shown in FIG. 2A, since the 0th-order mode light has a normal distribution of light intensity and phase, a centrally symmetric light beam is emitted from the end face of the main waveguide 125.
This light beam is linearly polarized in the TM mode direction.

The linearly polarized light emitted is a quarter wavelength plate 12
1 is converted into circularly polarized light, and the scanning device 122
Is scanned by the condenser lens 110 and condensed on the object 111 to be measured by the condenser lens 110.

The reflected light from the object 111 to be inspected is condensed by the condenser lens 110 on the end face of the main waveguide 125 and is incident on this. The reflected light of the object 111 to be inspected is converted into linearly polarized light (TE mode direction) in a polarization direction orthogonal to the illumination light by passing through the quarter-wave plate 121 when condensed.

At this time, if the object 111 to be inspected has an inclination or a step, an asymmetrical phase distribution is generated in the beam of the reflected light due to the optical path difference due to the inclination or the step. Also, the object to be inspected 1
If there is a distribution of reflectance in 11 and the like, a distribution of reflected light intensity occurs, so that an asymmetric intensity distribution occurs in the beam of reflected light.

The light incident on the main waveguide 125 propagates in the TE mode. Since the main waveguide 125 is a double mode with respect to the TE mode, when the beam of the reflected light has an asymmetrical phase distribution or intensity distribution, the zero-order mode and the first-order mode are excited in the main waveguide 125. . The 0th-order mode light is center-symmetrical as shown in FIG. 2A, but the 1st-order mode light is asymmetrical as shown in FIG. 2B. Therefore, both the 0th-order mode light and the 1st-order mode light are Is excited, the interference light of both propagates while meandering through the main waveguide 125.

The light propagating through the main waveguide 125 reaches the branching portion 108, and the two branch waveguides 106 and 107 on both sides are provided.
Incident on and propagates in the 0th-order mode of TE. Object to be inspected 11
When 1 has an asymmetry such as an inclination, a step, a reflectance distribution, etc., the interference light of the 0th-order mode and the 1st-order mode is split.
Are asymmetrical in the two branch waveguides 106, 1
The amount of light incident on 07 is different. Photodetector 103, 104
Detects the amount of light propagating through the branch waveguides 106 and 107.

The differential amplifier 112 includes photodetectors 103 and 1
By obtaining the difference between the outputs of 04, a minute step on the object 111 or a change in reflectance is detected. Control device 113
Is a combination of the position information obtained from the scanning device 122 and the step or reflectance change output of the differential amplifier 112, and an XY two-dimensional image of the object 111 to be inspected is displayed on the display device 1.
14 is displayed.

Like the inclination or step of the object 111 to be inspected,
When observing information that gives an asymmetrical phase distribution to the light beam, the length L of the reflected light entering the main waveguide 125 propagating in the double mode is

[0040]

## EQU1 ## L = L _c (2m + 1) / 2 (m = 0, 1,
2, ...), the most efficient detection is possible.

When observing information that gives an intensity distribution to the light spot, such as the reflectance distribution of the object 111 to be inspected, the length of the reflected light incident on the main waveguide 125 propagating in the double mode. L

[0042]

[Equation 2] By setting L = m · L _c (m = 1, 2, ...), detection can be performed most efficiently.

However, L _c is a perfect coupling length (length at which the phase difference between the 0th-order mode and the 1st-order mode is π).

When it is desired to detect the phase distribution and the intensity distribution together, the phase distribution and the intensity distribution can be arbitrarily set by setting an arbitrary length L between (Equation 1) and (Equation 2). It is possible to detect in combination with the ratio of.

The reason why the phase distribution or the intensity distribution can be detected most efficiently when L is determined so as to satisfy (Equation 1) or (Equation 2) is described in JP-A-4-2089.
Since it is described in detail in Japanese Patent No. 13, the description will be omitted.

Here, the length L by which the light incident on the main waveguide 125 propagates in the double mode is the main waveguide 125.
The TE light incident from the end face of is propagated in the double mode,
It is the length until branching into the branch waveguides 106 and 107, but this length may not match the length of the main waveguide 125. This is because in FIG. 1, the angle θ formed by the central branch waveguide 105 and the side branch waveguides 106 and 107.
Although it is illustrated largely, it is actually desirable to set the angle θ to a very small angle of about 1/100 rad in order to improve the coupling efficiency of the branched portion. When the angle θ is set to such a small angle, the TE mode light propagating in the double mode through the main waveguide 125 is geometrically branched into three branch waveguides 105, 106 and 107. After that, in the region where the distance between the three branch waveguides 105, 106 and 107 is very narrow, the three branch waveguides 10
Propagate in double mode so as to cross 5, 106 and 107. Therefore, when determining the length of the main waveguide 125, it is necessary to consider the region where the branch waveguides 105, 106 and 107 propagate in the double mode. Specifically, the length of the reflected light that has entered from the end face of the main waveguide 125 actually propagates in the double mode, that is, the length of the main waveguide 125 and the length of the region that propagates in the branch waveguide in the double mode. Is set to L, and L is determined so as to satisfy (Equation 1) or (Equation 2).

As described above, in this embodiment, the main waveguide 12
5 has a structure in which the metal film 115 is loaded on the buried type waveguide, so that the TE mode light acts as a double mode buried type waveguide and the TM mode light acts as a single mode loaded type waveguide. I decided to do it. As a result, even if the center line of the central branch waveguide 105 and the center line of the main waveguide are not completely coincident with each other and the branch portion 108 does not have a completely symmetrical shape, the illumination is performed. Since the TM mode light of the light always propagates through the main waveguide in the 0th mode, it is possible to irradiate the test object 111 with a light beam having a normal distribution.

Therefore, since the reflected light contains only the asymmetry information of the object to be inspected, it is possible to detect the inclination and step information of the object to be inspected and the reflectance distribution information with high accuracy.

In the main waveguide 125, the metal film 115
Although it is desirable that the center line of the loaded waveguide according to (4) be coincident with the center line of the buried waveguide, it is not always required to coincide with the center line. If they do not match, the reflected light from the object 111 to be inspected is always biased and incident on the embedded waveguide, so that the first-order mode is excited even if the object to be inspected has no phase distribution or intensity distribution. And detectors 103, 10
There is a difference in the amount of light detected at No. 4. Since this difference in light amount is a constant amount that is determined by the deviation of the center line between the loaded waveguide and the buried waveguide, the difference in light amount is obtained in advance, and the controller 113 corrects this difference in light amount. This can be handled by configuring

The single mode waveguide formed by loading the metal film is formed by the branch waveguide 105 and the main waveguide 12.
Since it can be manufactured relatively easily as compared with the case where the center lines of 5 are formed so as to be completely aligned with each other, the manufacturing cost can be reduced.

Further, in order to form the main waveguide 125, a mask is formed at the position of the metal film 115, and Ti is diffused from between the mask and the main waveguide 1.
A method of forming 25 buried waveguides and then forming a metal film at the position of this mask can be used. By using this method, in the main waveguide 125,
The center lines of the loaded waveguide and the buried waveguide can be aligned.

Further, in the configuration of FIG. 1, by connecting the above-mentioned metal film 115 to a power source, the main waveguide 12
It is possible to adopt a configuration in which a voltage is applied to 5. In FIG. 1, the waveguide substrate 101 is made of LiNb having an electro-optical effect.
Since it is composed of O _3, by applying a voltage to the main waveguide 125, the electro-optic effect of LiNbO ₃ changes the refractive index for TE mode light according to the applied voltage. The complete bond length L _c changes according to the change amount of the refractive index. Therefore, even if the geometric length L of the main waveguide 125 is constant, it is possible to satisfy (Equation 1) or (Equation 2) by changing L _c with the voltage.

As a result, when it is desired to detect the asymmetrical phase distribution information such as the inclination or step of the object to be detected with the highest sensitivity, a voltage satisfying (Equation 1) is applied to detect the light intensity distribution with the highest sensitivity. If desired, a voltage can be applied to satisfy (Equation 2). Also, if you want to detect the phase distribution information and the light intensity distribution information together,
The voltage can be applied to set any value of L between (Equation 1) and (Equation 2). In addition, L may be set so that one of (Equation 1) and (Equation 2) is satisfied when a voltage is not applied, and the other is satisfied when a voltage is applied. it can.

In the structure of FIG. 1, the metal film 115 is arranged in the entire longitudinal direction of the main waveguide 125, but it may be arranged only in a part of the longitudinal direction.
In this case, the position of the metal film 115 is determined so that the end face portion of the main waveguide 125 becomes a single mode waveguide for TM mode light. For example, the metal film 115 is arranged in a region where the metal film 115 is continuous with the end surface.

Further, the main waveguide 125 of the above-mentioned embodiment is used.
Loads a pair of metal films 115 and acts as a loading type single mode waveguide for TM mode light, and acts as a buried type double mode waveguide for TE mode light. However, not limited to this configuration, it is also possible to configure a main waveguide that acts as a loaded single mode waveguide for TE mode light and acts as a buried double mode waveguide for TM mode light.

This can be realized, for example, by using a configuration in which a pair of amorphous silicon films are loaded instead of the pair of metal films 115 of the main waveguide 125. This is because, when the amorphous silicon film is arranged, the equivalent refractive index of TM mode light and the equivalent refractive index of TE mode light are changed by selecting the film thickness of the amorphous silicon film. That is, at a certain film thickness, the equivalent refractive index of TM mode light does not change significantly, but the equivalent refractive index of TE mode light becomes remarkably small. Also, with another film thickness, T
The equivalent refractive index of E-mode light does not change significantly, but T
The equivalent refractive index of M-mode light is significantly reduced.

Therefore, in the structure of the main waveguide 125 of FIG. 1, an amorphous silicon film is used in place of the metal film 115, and this film thickness is appropriately selected.
Single mode waveguide loaded with mode light, TM
It is possible to form a buried main waveguide of a double mode waveguide for mode light. Further, by making the amorphous silicon film have a different thickness, it is possible to form a main waveguide of a single mode waveguide for TM mode light and a double mode waveguide for TE mode light.

Although LiNbO ₃ is used as the waveguide substrate in the above embodiment, the present invention is not limited to this, and LiTa
O ₃ , Al ₂ O ₃ , Si, SiO ₂ , GaAs, InP, soda glass, quartz or the like can be used. LiTaO
_{When 3} , ₃ , GaAs and InP are used, the perfect coupling length L _c can be changed by applying an electric voltage to the metal film due to the electro-optical effect. GaA
When s and InP are used, the detector and the light source can be integrally formed on the waveguide substrate.

In the above-described embodiment, the metal film 115 is directly mounted on the substrate 101.
A buffer layer may be arranged between the semiconductor layer 01 and the metal film 115. The same applies when an amorphous silicon film is used instead of the metal film 115.

[0060]

According to the present invention, it is possible to propagate the illumination light only in the 0th mode in the waveguide and irradiate the object to be inspected with a centrosymmetrical light spot, though it has a structure that can be easily manufactured. It is possible to provide a modal interference type laser scanning microscope.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a mode interference type laser scanning microscope according to an embodiment of the present invention.

2A and 2B are graphs showing electric field distributions of a 0th-order mode and a 1st-order mode propagating in a waveguide.

FIG. 3 is a block diagram showing a configuration of a conventional mode interference type laser scanning microscope.

[Explanation of symbols]

1, 101 ... Optical waveguide substrate, 2, 102 ... Light source, 3,
4, 103, 104 ... Detectors, 5, 6, 7, 105, 1
06, 107 ... Branch waveguide, 8, 125 ... Main waveguide, 1
5, 108 ... Bifurcation part, 10, 110 ... Lens, 11, 1
11 ... Object to be inspected, 12, 112 ... Differential amplifier, 113 ...
Control device, 114 ... Display device, 115 ... Metal film.

Claims (12)

[Claims] 1. An illumination unit for irradiating an object to be inspected with light,
A detection part for detecting reflected light from the object to be inspected; and a waveguide part, wherein the waveguide part comprises a main waveguide, and a branch part for branching the main waveguide into three waveguides. And three branch waveguides connected to a branch portion, wherein the illumination unit is arranged so that light is incident on a central branch waveguide of the three branch waveguides, The detection unit is arranged to detect the light propagating in the branch waveguides on both sides of the three branch waveguides, and the waveguide unit is configured to detect the light emitted by the illumination unit in the central branch waveguide. , The branch portion, the main waveguide is sequentially propagated and emitted from the end face of the main waveguide toward the object to be inspected, the reflected light from the object to be inspected is incident from the end face, and the main waveguide, the branch portion, both Arranged so as to propagate in the order of the side branch waveguides and lead to the detection unit, and at least a part of the main waveguide is a loading type. The loaded type portion of the main waveguide is a double mode waveguide for one of TE mode light and TM mode light, and a single mode waveguide for the other, and a mode interference laser Scanning microscope. 2. The waveguide according to claim 1, wherein the main waveguide is T
Single mode waveguide for M mode light and TE
A mode interference laser scanning microscope characterized by being a double mode waveguide for mode light. 3. The main waveguide according to claim 2, wherein the main waveguide is T
A mode interference laser scanning microscope, which is a loaded waveguide for M-mode light and a buried waveguide for TE-mode light. 4. The main waveguide according to claim 3, wherein a pair of metal films are loaded on the buried type waveguide, and the pair of metal films form a center line of the buried type waveguide. A mode interference laser scanning microscope, which is characterized in that it is arranged in a sandwiched manner. 5. The TM of the main waveguide according to claim 1.
A mode interference type laser scanning microscope, wherein a center line of a portion for propagating mode light coincides with a center line of a portion for propagating TE mode light. 6. The TM-mode light of the light emitted from the end face of the main waveguide is irradiated onto the object to be inspected, and the reflected light of the object is reflected by the T-wave of the main waveguide according to claim 1.
A mode interference type laser scanning microscope further comprising a polarizing means for converting the light into polarized light in the E-mode light direction and making it incident on the end face of the main waveguide. 7. The main waveguide section according to claim 1, wherein:
The region including at least the end face portion is TE mode and T
A mode interference type laser scanning microscope characterized by being a single mode waveguide for one of M mode light. 8. The length L of a region, in the waveguide portion, in which light incident from an end face of the main waveguide propagates in a double mode in the waveguide portion is a 0th-order mode and a 1st-order mode in this region. _Let L _c be the full bond length of L = L _c · m (m = 1, 2, ...), and L = L _c (2m + 1) / 2 (m = 0, 1, 2 ,.・
A mode interference type laser scanning microscope characterized by satisfying any one of the relations of 9. The main waveguide according to claim 1, wherein the main waveguide is made of a material having an electro-optic effect, and the loaded portion of the main waveguide is loaded with a metal film. Is a mode interference type laser scanning microscope, which also serves as a voltage application section for applying a voltage to the main waveguide. 10. The length L of a region, in the waveguide part, in which the TE mode light incident from the end face of the main waveguide propagates in a double mode in the waveguide part, when a voltage is applied to the metal film. In the region of
When the complete coupling length between the 0th-order mode and the 1st-order mode for the E mode is L _c , L = L _c · m (m = 1, 2, ...) And L = L _c (2m + 1) / 2 (m = 0, 1, 2, ...
A mode interference type laser scanning microscope characterized by satisfying any one of the relations of 11. A main waveguide, a branch portion for branching the main waveguide into three waveguides, and three branch waveguides connected to the branch portions, the center of the branch waveguides. Light incident on the branch waveguide of the central propagating waveguide, the branch portion, the main waveguide is propagated in this order, the light incident on the main waveguide, the main waveguide, the branch portion,
Propagating in the order of the branch waveguides on both sides, the main waveguide is at least partially loaded, and the loaded portion of the main waveguide is used for one of TE mode light and TM mode light. An optical information detection device, which is a double-mode waveguide and a single-mode waveguide for the other. 12. The detector according to claim 11, further comprising a detector for detecting light that has entered the main waveguide, is branched at the branch portion, and propagates through the branch waveguides on both sides. Optical information detection device.