JPH11194373A - Optical element, deflecting element using optical element, and method and device for optical control - Google Patents

Abstract

PROBLEM TO BE SOLVED: To deflect light fast at a desired deflection angle. SOLUTION: This device consists of at least a light source 12 for signal light, a light source 11 for control light having a different wavelength from the light source 12 for the signal light, a wedgelike light intensity distribution adjusting means 6, and an optical element 9 formed of a light responding composition. In this optical element, a refractive index distribution is formed by the control light and the deflection of the signal light is controlled by this refractive index distribution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element useful in the field of optoelectronics (photonics) such as optical communication and optical information processing, a deflecting element using the same, a light control method and a light control device. . In particular, the present invention relates to an optical element that deflects light (signal light) based on a change in the refractive index of the optical element, a deflection element using the optical element, a light control method, and a light control device.

[0002]

2. Description of the Related Art As means for deflecting light, the following method is generally employed.

(1) Shake the mirror mechanically.

(2) The polygon mirror is rotated mechanically.

(3) Use the acousto-optic effect.

(4) The electro-optic effect is used.

However, the deflection method of mechanically swinging the mirror is inexpensive, but has disadvantages in that it is inaccurate and cannot respond to high frequencies. The method using a polygon mirror is very expensive. The method using the acousto-optic effect is expensive and has a drawback that it does not respond to high frequencies unless condensed using a lens or the like. Further, the method using the electro-optic effect has disadvantages of being expensive, large, and having a small deflection angle.

In view of such circumstances, a method of modulating light by generating a refractive index distribution in a medium depending on temperature is disclosed in
No. -14221. This JP
In the technique disclosed in JP-A-124221, heat is applied to a medium by a heating resistor, a refractive index distribution is generated in the medium, and light is deflected. The light spot blinks depending on whether or not the deflected light is blocked by the light blocking plate.

[0009]

However, according to the method disclosed in Japanese Patent Application Laid-Open No. 60-124221, heat is generated by a heating resistor and the medium is heated by heat conduction. "Inherently.
That is, due to the spread of heat, a fine thermal gradient cannot be given in a wide area, and it is difficult to obtain a desired refractive index distribution. Furthermore, even if the photolithography technology used in semiconductor integrated circuits is employed, the fine processing of the heating resistor is extremely difficult in practice, has a certain limit, and the element must be enlarged. . As the size of the element increases, the optical system also increases in complexity and size. In addition, heat is generated by the heating resistor, and the medium is heated by heat conduction.
It has a disadvantage that response is slow and the frequency of refractive index change cannot be increased as an essential problem.

In view of the above problems, the present invention provides a wedge-shaped refractive index distribution in a predetermined area, and accurately deflects transmitted light (signal light) to a desired deflection angle by the refractive index distribution. An object of the present invention is to provide an optical element capable of performing the following.

Another object of the present invention is to provide an optical element which raises the frequency of a change in the refractive index and enables high-speed deflection control using the change in the refractive index.

Still another object of the present invention is to provide an optical element which enables light deflection with a sufficient deflection angle with as low an optical power as possible.

Still another object of the present invention is to provide an inexpensive and highly accurate deflection element.

Still another object of the present invention is to provide a deflection element which enables high-speed deflection control.

Still another object of the present invention is to provide a deflecting element capable of deflecting light at a sufficient deflection angle with as low an optical power as possible.

Still another object of the present invention is to provide a light control method capable of easily and accurately deflecting light.

Still another object of the present invention is to provide a light control method capable of increasing the frequency of a change in the refractive index in an optical element, thereby enabling high-speed deflection control.

Still another object of the present invention is to provide a more energy-saving and economical light control method that performs light deflection with a sufficient deflection angle with the lowest possible light power.

Still another object of the present invention is to provide a light control device which has a simple structure, is inexpensive, and can accurately deflect light.

Still another object of the present invention is to provide a light control device having a compact device configuration and capable of high-speed deflection control.

Still another object of the present invention is to provide a light control device which can perform light deflection with a sufficient deflection angle with as low a light power as possible and has a low running cost.

[0022]

In order to achieve the above object, a first feature of the present invention is to form a wedge-shaped refractive index distribution inside by irradiating light with a wedge-shaped light intensity distribution. That is, the optical element is made of a photoresponsive composition that is configured as desired. In order to form a wedge-shaped refractive index distribution inside, in order to form a wedge-shaped light intensity distribution, an intensity distribution adjusting means is arranged in a predetermined positional relationship such as near the optical element, and the wedge-shaped What is necessary is just to form a temperature distribution. It goes without saying that control light such as laser light having a wavelength absorbed by the optical element is selectively applied to the optical element. In order to deflect the signal light using this optical element, the signal light having a wavelength different from that of the control light may be deflected by a wedge-shaped refractive index distribution, and only the signal light may be extracted. For example, the intensity distribution adjusting means may be constituted by a filter having a square or rectangular window and having a wedge-shaped intensity distribution of light transmitted through the window. Since a predetermined portion of the photoresponsive composition is directly heated by light, there is no time delay required for raising the temperature of the heating element itself, and there is no time delay required for heat conduction, so that a desired temperature distribution can be achieved at high speed.
Therefore, a desired refractive index distribution can be formed in a very short time. By changing the intensity of the control light applied to the photoresponsive composition in the optical element (for example, changing the power of the light emitted from the light source), the refractive index can be changed and the deflection angle can be freely changed within a predetermined range. It is possible. Further, since the photoresponsive composition can be easily produced by a known technique, the price of an optical element comprising the photoresponsive composition according to the first aspect of the present invention is low.

A second feature of the present invention is that the optical element comprises at least an optical element comprising a photoresponsive composition, and an intensity distribution adjusting means for irradiating the optical element with light in a wedge-shaped light intensity distribution. It is a deflecting element that forms a temperature distribution in an optical element by light and deflects signal light having a wavelength different from that of the control light by a refractive index distribution based on the temperature distribution. The intensity distribution adjusting means according to the second feature of the present invention may be constituted by a filter having a square or rectangular window and having a wedge-shaped intensity distribution of light transmitted through the window. The window of the intensity distribution adjusting means is irradiated with light (for example, a semiconductor laser beam) emitted from a light source, and the light transmitted through the window is imaged on a light-responsive composition in the optical element to thereby provide a predetermined light in the optical element. A heat energy distribution (temperature distribution) is formed, resulting in a wedge-shaped refractive index distribution. Since a predetermined portion of the photoresponsive composition is directly heated by light, a desired temperature distribution and refractive index distribution can be formed in a short time. Therefore, the deflection frequency is high, and about 10 kHz can be easily achieved. If a photoresponsive composition is selected, a high deflection frequency of about 1 MHz is possible. By changing the intensity of control light applied to the photoresponsive composition in the optical element (for example, changing the power of light emitted from the light source), it is possible to change the refractive index and change the deflection angle. Since the predetermined portion of the photoresponsive composition is directly heated by light, the heating efficiency is high, and the deflection angle in a predetermined range can be freely changed with low light power.

A third feature of the present invention is to irradiate an optical element made of a photoresponsive composition with control light having a wedge-shaped distribution of control light having a wavelength absorbed by the optical element;
Forming a wedge-shaped refractive index distribution in the optical element by irradiating the control light, and irradiating the optical element having the wedge-shaped refractive index distribution with signal light having a wavelength different from that of the control light, And a light control method using an optical element that includes at least a step of performing deflection and controlling light. In order to have a wedge-shaped light intensity distribution, a filter having a square or rectangular window and having a wedge-shaped intensity distribution of light transmitted through this window may be used. The window of the filter is irradiated with light emitted from a light source, and the light transmitted through the window is imaged on a light-responsive composition in the optical element, whereby a predetermined thermal energy distribution (temperature distribution) is formed in the optical element. Is formed, resulting in a wedge-shaped refractive index distribution. Since a predetermined portion of the photoresponsive composition is directly heated by light, a temperature distribution and a refractive index distribution can be formed at high speed. Therefore, the deflection frequency is high and 10 k
Hz can be easily achieved. If you choose a photoresponsive composition,
Deflection frequencies as high as 1 MHz are possible. By changing the intensity of the control light applied to the photoresponsive composition in the optical element, the refractive index can be changed and the deflection angle can be changed at a high speed. . Since a predetermined portion of the photoresponsive composition is directly heated by light, energy efficiency is high and a large deflection angle can be obtained. Therefore, the deflection angle in a predetermined range can be freely changed with low optical power.

A fourth feature of the present invention is that a deflection element comprises at least an optical element made of a photoresponsive composition, and intensity distribution adjusting means for irradiating the optical element with light with a wedge-shaped light intensity distribution; A first light source that outputs light (control light) having a wavelength absorbed by the optical element; and a second light source that outputs light (signal light) having a different wavelength from the first light source. The light from the first light source (control light) generates a refractive index distribution in the optical element.
Is a light control device using an optical element for controlling the deflection of the light (signal light) of the light source. The intensity distribution adjusting means according to the third feature of the present invention may be constituted by a filter having a square or rectangular window and having a wedge-shaped intensity distribution of light transmitted through the window. The window of the intensity distribution adjusting means is irradiated with light (control light) emitted from a light source, and the light transmitted through this window is imaged on a light-responsive composition in the optical element, so that a predetermined heat energy is generated in the optical element. A distribution (temperature distribution) is formed, resulting in a wedge-shaped refractive index distribution. Since a predetermined portion of the photoresponsive composition is directly heated by light, a temperature distribution and a refractive index distribution can be formed at high speed. Therefore, the deflection frequency is high, and about 10 kHz can be easily achieved. Furthermore, if a photo-responsive composition is selected, 1 MHz
Higher deflection frequencies are possible. The deflection angle can be changed by changing the intensity of the control light applied to the photoresponsive composition in the optical element. Since light directly heats a predetermined portion of the photoresponsive composition, the energy efficiency is high and the power consumption of the device is low. Further, the deflection angle in a predetermined range can be freely changed with a low optical power, which is efficient. In the fourth aspect of the present invention, in order for the light (control light) of the first light source and the light (signal light) of the second light source to enter the optical element with substantially the same optical axis, light mixing such as a beam splitter is required. A vessel may be used. In order to separate the control light and the signal light output from the optical element, a predetermined wavelength selection filter may be used. In addition, it is a matter of course that an optical system using a known lens or the like may be used in order to efficiently input the control light and the signal light with a beam diameter having a size determined in the optical element. In any case, since the light control device can be formed with a simple device configuration, the entire device becomes compact and its price is low.

[0026]

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

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
1 shows a schematic configuration example of a light control device according to an embodiment. The light control device according to the first embodiment of the present invention includes a light source (first light source) 11 for control light, a light source (second light source) 12 for signal light, and a light source as illustrated in FIG. It comprises a modulator 3, a shutter 4, a lens group 5, an ND filter 6, a lens 7, an optical mixer 8, an optical element 9 of the present invention, and a wavelength selective transmission filter 10.

A laser device is suitable for the light source 11 of the control light. The light control device according to the first embodiment of the present invention is an example in which a gas laser or a solid-state laser is used as control light. The oscillation wavelength and output are appropriately selected according to the wavelength of the signal light targeted by the light control method of the present invention and the response characteristics of the photoresponsive composition used. There is no particular limitation on the type of laser oscillation, and any type can be used depending on the oscillation wavelength band, output, economy, and the like. Also. The light from the laser light source may be used after the wavelength is converted by a nonlinear optical element. Specifically, for example, an argon ion laser (oscillation wavelength: 457.9 to 514.5 nm), a helium-neon laser (633n)
m), a solid-state laser such as a ruby laser or an Nd: YAG laser, a dye laser, or the like can be suitably used. As a light source (second light source) 12 for signal light, a laser device having a different wavelength from the light source (first light source) 11 for control light is used. As the signal light source 12, not only coherent light from a laser light source but also non-coherent light can be used. In addition to laser devices, light sources that provide monochromatic light, such as light-emitting diodes and neon discharge tubes, and continuous spectral light from tungsten bulbs, metal halide lamps, xenon discharge tubes, etc., are used as monochromatic light filters and monochromators. Is also good.

The light modulator 3 is used to change the control light intensity to change the deflection angle. For example, an AO modulator or an EO modulator may be used. The shutter 4 is used to shield light when control light is not required, and need not be used when the light modulator 3 is used instead. When the shutter 4 is used, any type can be used. For example, an optical chopper, a mechanical shutter, a liquid crystal shutter, an optical Kerr effect shutter, a Pockels cell, a photoacoustic element, and the like can be used. It can be appropriately selected and used in consideration of the operation speed.

The lens group 5 is used to irradiate the optical element 9 with light of a gas laser or solid-state laser which is the light source 11 of the control light to a predetermined size.

The ND filter 6 is used to make the intensity distribution of the control light into a wedge shape as shown in FIG. 2, the x-axis is the optical axis direction of the control light, the y-axis is a direction perpendicular to the plane of FIG. 1, and the z-axis is the optical axis (x
Axis).

The intensity distribution of the laser beam has a Gaussian distribution as shown in FIG. If the lens diameter is larger than the laser light, the laser light passing through the lens has a Gaussian distribution. In this state, the laser light incident on the ND filter 6 has a Gaussian distribution. In the light control device according to the first embodiment of the present invention, a part of the laser light having the Gaussian distribution is extracted using the laser light transmission window 63 on the yz plane as shown in FIG. FIG. 3 (b)
The outer circumference 62 is a position where the laser beam intensity can be regarded as substantially 0% in a Gaussian distribution on a concentric circle, that is, a beam diameter. That is, a predetermined laser light transmission window 63 is provided in front of the ND filter 6 or in front of the optical element 9 in order to extract a part of the laser light having a Gaussian distribution. As shown in FIG. 3B, the laser light transmission window has a line segment where one side (lower side) in the y-axis direction passes through the position of the maximum intensity (100%) of the Gaussian distribution, and the other side in the y-axis direction. Is a line segment passing through the position of about 30% of the center intensity of the Gaussian distribution, and both sides (right side and left side) in the z-axis direction are about 70% of the Gaussian distribution.
Is a rectangular window constituted by a line segment passing through the position. This laser light transmission window has a size of about 0.03 on the optical element 9.
It is from mm square to 0.1 mm square. The intensity distribution adjusting means of the present invention is constituted by a combination of the laser light transmission window 63 and the ND filter 6 which are omitted in FIG. 1, and a wedge-shaped light intensity having a refractive index changed in the z-axis direction as shown in FIG. Make distribution. The intensity distribution adjusting means of the present invention and the optical element 9 constitute a deflection element of the present invention.

Light having a wedge-shaped light intensity distribution as shown in FIG. 2 is incident on the optical element 9, and the optical element 9 that has absorbed the light undergoes a change in the refractive index due to heat caused by the light absorption. The change in the refractive index is substantially proportional to the incident light intensity when the incident light intensity is below a certain value. Therefore, when wedge-shaped light is incident in the one-dimensional direction, a wedge-shaped refractive index distribution in which the refractive index changes in the z-axis direction is generated. As the photoresponsive composition used for the optical element 9, various known compounds such as a compound semiconductor single crystal may be used. Specific examples of these photoresponsive compositions will be described later.

When the signal light is made to enter the optical element 9 with the optical axis substantially the same as the control light using the optical mixer 8, the signal light becomes z
The light is deflected by a wedge-shaped refractive index distribution in which the refractive index changes in the axial direction. The angle of deflection (deflection angle) is 0 ° to 3 °.
In the range of 0 °, it can be changed by the power of the control light. When the power of the control light is zero, no deflection is performed. The deflection angle increases as the power of the control light increases from zero. Since a predetermined portion of the photoresponsive composition is directly heated by light, the energy efficiency is high. For example, when a helium-neon laser (633 nm) is used as the control light, 20 to 1 is used.
A desired deflection angle (within a range of 0 ° to 30 °) can be freely obtained with a low optical power of about 30 mW. The optical mixer 8 is used for adjusting the optical paths of the control light and the signal light incident on the optical element. Any of a polarizing beam splitter, a non-polarizing beam splitter, or a dichroic mirror can be used.

The control light is cut by the wavelength selection filter 10, only the signal light is transmitted, and the signal light is deflected. As means for separating the signal light and the control light having different wavelengths from each other, a prism, a diffraction grating, a dichroic mirror, or the like can be used. As the wavelength selective transmission filter 10, if it is a wavelength selective transmission filter that can completely block light in the wavelength band of control light and efficiently transmit light in the wavelength band of signal light,
Any known one can be used. For example, plastic or glass colored with a dye, glass having a multilayer dielectric film on its surface, or the like can be used.

Here, specific examples of the photoresponsive composition used for the optical element 9 will be described. This photoresponsive composition irradiates the control light with a wedge-shaped light intensity distribution, and reversibly changes the refractive index due to the temperature rise occurring in the area where the control light is absorbed and the surrounding area. Any material that absorbs light may be used. For example, (a) a single crystal of a compound semiconductor or a dispersion of fine particles of the compound semiconductor in a matrix material. As the compound semiconductor, for example, GaAs, GaAsP, G
aAlAs, InP, InAs, PbTe, InGaAs
sP, ZnSe, or the like may be used.

(B) Single-element semiconductor single-crystal thin films, polycrystalline thin films or porous thin films, or fine particles of the single-element semiconductor dispersed in a matrix material. As a single element semiconductor, silicon (Si), germanium (Ge), selenium (Se), tellurium (Te), or the like may be used.

(C) A single crystal of a metal halide doped with a different metal ion or a dispersion of fine particles of the metal halide in a matrix material. As the metal halide, potassium bromide, sodium chloride, copper bromide, copper chloride, cobalt chloride, or the like may be used.

(D) A single crystal of cadmium chalcogenide such as CdS, CdSe, CdSeS, CdSeTe doped with a foreign metal ion such as copper, or a dispersion of fine particles of these cadmium chalcogenides in a matrix material.

(E) Single crystals (so-called laser crystals) corresponding to jewels doped with metal ions such as ruby, alexandrite, garnet, Nd: YAG, sapphire, Ti: sapphire, Nd: YLF; metal ions (for example, iron Ion) doped lithium niobate (LiNbO ₃ ), LiB ₃ O ₅ , LiTaO ₃ , KT
iOPO ₄ , KH ₂ PO ₄ , KNbO ₃ , BaB ₂ O ₂
Ferroelectric crystals such as quartz glass, soda glass, borosilicate glass, and other glasses doped with metal ions (eg, neodymium ions, erbium ions, etc.).

(F) A dye dissolved or dispersed in a matrix material.

And the like.

These light-responsive compositions (light-absorbing materials)
Among them, those in which a dye is dissolved or dispersed in the matrix material (f) are particularly preferably used in the present invention because the selection range of the matrix material and the dye is wide and the processing into a thin-film optical element is easy. be able to. The deflection frequency of the light control device according to the first embodiment of the present invention is high,
A frequency of about 10 kHz can be easily attained. In particular, if an appropriate light-absorbing material is selected from the above-mentioned photoresponsive compositions, 10
High deflection frequencies on the order of 0 kHz to 1 MHz are also possible.

Specific examples of the dye which can be used in the present invention include, for example, xanthene dyes such as rhodamine B, rhodamine 6G, eosin and phloxin B, acridine dyes such as acridine orange and acridine red, ethyl red, methyl Azo dyes such as red, porphyrin dyes, phthalocyanine dyes, cyanine dyes such as 3,3′-diethylthiacarbocyanine iodide, 3,3′-diethyloxadicarbocyanine iodide, ethyl violet, Victoria Blue Triarylmethane dyes such as R can be suitably used.

In the present invention, these dyes can be used alone or in combination of two or more.

The matrix material that can be used in the present invention includes (1) high transmittance in the wavelength region of light used in the light control method of the present invention, and (2) dye or various fine particles used in the present invention. Can be used as long as it satisfies the conditions that it can be dissolved or dispersed with good stability, and (3) it has self-shape retention if necessary.

As the inorganic matrix material, for example, a single crystal of a metal halide, a single crystal of a metal oxide, a single crystal of a metal chalcogenide, quartz glass, soda glass, borosilicate glass, etc., or a so-called sol-gel method can be used. For example, a low-melting glass material obtained can be used. Further, as the organic matrix material, for example, various organic polymer materials can be used.

A known method can be used for dissolving or dispersing the dye in these matrix materials.
For example, (a) a method in which a dye and a matrix material are dissolved in a common solvent and mixed, and then the solvent is removed by evaporation; (b) a dye is dissolved in a raw material solution of an inorganic matrix material produced by a sol-gel method. Or a method of forming a matrix material after dispersing, (c) into a monomer of the organic polymer matrix material, using a solvent if necessary,
A method in which a matrix material is formed by dissolving or dispersing a dye and then polymerizing or polycondensing the monomer; or (d) dissolving a solution in which a dye and an organic polymer matrix material are dissolved in a common solvent; A method in which both the plastic organic polymer matrix material is dropped into a solvent in which both are insoluble, the resulting precipitate is filtered off, dried, and then heated and melt-processed can be suitably used. It is known that a special association called "H-aggregate" or "J-aggregate" can be formed by aggregating the dye molecules by combining the dye and the matrix material and devising a processing method. The dye molecules therein may be used under conditions that form such an aggregated or associated state.

A known method can be used to disperse the above-mentioned various fine particles such as semiconductors and metal halides in these matrix materials. For example, (a) a method in which these fine particles are dispersed in a solution of a matrix material or a solution of a precursor of the matrix material, and then the solvent is removed; (b) into a monomer of the organic polymer matrix material, if necessary. (C) using a solvent to disperse fine particles and polymerizing or polycondensing monomers to form a matrix material; (c) using a metal salt such as cadmium perchlorate or gold chloride as a precursor of fine particles; A method of dissolving or dispersing in a polymer matrix material and then treating with a hydrogen sulfide gas to precipitate cadmium sulfide fine particles, or heat treatment to deposit gold fine particles in the matrix material; (d) or A method of growing a matrix material using a dopant gas containing these fine particles in chemical vapor deposition (CVD), It can be suitably used a method in which to deposit the matrix material using a target containing these microparticles in Taringu method.

The photoresponsive composition used in the optical element 9 of the present invention can improve the workability and the stability of the optical element as long as the function is not impaired.
In order to improve the durability, known additives such as an antioxidant, an ultraviolet absorber, a singlet oxygen quencher, and a dispersing aid may be contained.

[Method of Manufacturing Optical Element] The method of manufacturing the optical element 9 of the present invention is arbitrarily selected according to the configuration of the optical element 9 and the type of material to be used, and a known method can be used. For example, (A) When the light-absorbing material used for the light-responsive composition in the optical element is a single crystal, the light-absorbing layer film can be formed by cutting and polishing the single crystal.

(B) When producing a thin-film optical element using a combination of a light-absorbing layer film composed of a matrix material containing a dye and an optical glass, the light-absorbing layer film is formed by the methods listed below. Can be created.

(A) A solution in which a dye and a matrix material are dissolved is coated on an optical glass substrate used as a heat transfer layer film by a coating method, a blade coating method, a roll coating method, a spin coating method, a dipping method, a spraying method or the like. A method in which a light absorbing film layer is formed by coating using a coating method or printing by a printing method such as lithographic printing, letterpress printing, intaglio printing, stencil printing, screen printing, and transfer. In this case, an inorganic matrix material forming method by a sol-gel method can be used for forming the light absorbing film layer.

(B) A method of depositing on an optical glass substrate by an electrochemical film forming method such as an electrodeposition method, an electrolytic polymerization method, and a micelle electrolytic method (JP-A-63-243298).

(C) A Langmuir-Blodgett method in which a monomolecular film formed on water is transferred onto an optical glass substrate.

(D) When the organic polymer matrix material forming the light absorbing layer film is thermoplastic, a thin or thick film can be formed by using a hot pressing method (Japanese Patent Application Laid-Open No. 4-99609) or a stretching method. The model optical element can be made on an optical glass substrate.

(E) As a method utilizing the polymerization or polycondensation reaction of the raw material monomers, for example, when the monomer is a liquid, an optical glass substrate is formed by a method such as a casting method, a rear cushion injection molding method, and a photopolymerization method. How to deposit on top. Furthermore, if this liquid is vaporized, a plasma polymerization method can be used.

(F) Sublimation transfer method, vacuum deposition method, ion beam method, sputtering method, plasma polymerization method, CVD
And a method of depositing on an optical glass substrate by a method such as an organic molecular beam evaporation method (organic MBE method).

(G) Composite by spraying an organic optical material of two or more components in a solution or dispersion form from a spray nozzle provided for each component into a high-vacuum vessel, depositing it on a substrate, and performing heat treatment. Method of manufacturing optical optical thin film (Japanese Patent No. 25995)
No. 69) can also be used.

(C) In addition to the thin-film optical element using a combination of these optical glasses, it is also possible to use the dye dissolved or dispersed in a solution and put in a thin cell.

(Second Embodiment) FIG. 4 shows a schematic configuration example of a light control device according to a second embodiment of the present invention. The second embodiment is an example in which a semiconductor laser is used as control light. As exemplified in FIG. 4, the light control device according to the second embodiment of the present invention includes a semiconductor laser 21 as a control light source (first light source) and a signal light source (second light source). ) 22, lens group 5, ND filter 6,
It comprises a lens 7, a light mixer 8, an optical element 9 of the present invention, and a wavelength selective transmission filter 10.

The semiconductor laser 21 is made of GaAs, InGa
P, InGaAlP, InGaAlAs, GaAlAs
It is appropriately selected according to the oscillation wavelength and output of Sb, GaN, or the like. In particular, the wavelength of the semiconductor laser as the light source of the control light is selected to be different from the wavelength of the light source 22 of the signal light. The selection is made in consideration of the light absorption characteristics of the optical element 9.
The wavelength of the light of the semiconductor laser 21 may be converted by a nonlinear optical element before use.

The configuration shown in FIG. 4 basically has the same parts as the configuration shown in FIG. 1, but the optical modulator 3 and the shutter 4 shown in FIG. 1 are unnecessary. This is because the power supply for driving the semiconductor laser can be controlled, and the output of the semiconductor laser can be easily modulated or turned on / off. Although it is preferable to use a semiconductor laser also for the signal light source 22, it does not prevent using a gas laser or a solid-state laser other than the semiconductor laser. Further, not only coherent light from these laser light sources but also non-coherent light can be used. In addition to laser devices, light sources that provide monochromatic light, such as light-emitting diodes and neon discharge tubes, and continuous spectral light from tungsten bulbs, metal halide lamps, xenon discharge tubes, etc. may be used as monochromatic light filters and monochromators. good.

In the second embodiment of the present invention, a semiconductor laser (oscillation wavelength 780 n) is used as the signal light source 22.
m, a continuous oscillation output of 3 mW) is converted into substantially parallel light and irradiated onto an optical element at about 50 μm for use. On the other hand, a semiconductor laser (oscillation wavelength of 694 nm,
The energy distribution of the beam cross section is Gaussian distribution, the maximum output is 5
0mW) will be described.

The lens group 5 is used to irradiate the optical element 9 with the output light from the semiconductor laser 21 at a predetermined size. The beam divergence angle of the output light from the semiconductor laser 21 is generally 30 in an elliptical direction perpendicular to the active layer.
About 10 degrees in the direction horizontal to the active layer. The size of the laser beam having such a divergence angle is made substantially the same both in the horizontal direction and in the vertical direction so that the optical element 9
In order to irradiate the lens, a cylindrical lens 51 having a lens function in the vertical direction and having a focal length of about 10 mm and a cylindrical lens 52 having a lens function in the horizontal direction and having a focal length of about 30 mm were used.

The ND filter 6 is used to make the intensity distribution of the control light into a wedge shape as shown in FIG. 2 described in the first embodiment. The intensity distribution of the laser light has a Gaussian distribution as shown in FIG. If the lens diameter is larger than the laser light, the laser light passing through the lens has a Gaussian distribution. In the light control device according to the second embodiment of the present invention, a part of the Gaussian distribution laser light is extracted using a laser light transmission window (not shown in FIG. 4).
That is, in order to extract a part of the laser light having a Gaussian distribution, before the ND filter 6 or before the optical element 9,
A predetermined laser light transmission window is provided. As described in the first embodiment, this laser light transmission window is a rectangular window surrounding a position at 100% of the center intensity of the Gaussian distribution and arranged asymmetrically in the z-axis direction. In FIG. 4, the intensity distribution adjusting means of the present invention is constituted by a combination of a laser light transmission window (not shown) and the ND filter 6, and has a light intensity distribution as shown in FIG. The intensity distribution adjusting means of the present invention and the optical element 9 constitute a deflection element of the present invention. Light having a wedge-shaped light intensity distribution as shown in FIG. 2 is incident on the optical element 9, and the optical element 9 that has absorbed the light undergoes a change in the refractive index due to heat caused by the light absorption. The change in the refractive index is substantially proportional to the incident light intensity when the incident light intensity is below a certain value. Therefore, when wedge-shaped light is made incident in a one-dimensional direction, a wedge-shaped refractive index distribution is generated. As the optical element 9, a light-responsive composition (light-absorbing material) such as a semiconductor single-crystal thin film, a metal halide single-crystal thin film, or a material in which a dye is dissolved (or dispersed) in a matrix material as described in the first embodiment. (Refer to the first embodiment).

In the light control device according to the second embodiment of the present invention, when the signal light is made to enter the optical element 9 with the optical axis substantially the same as the control light using the optical mixer 8, the signal light is deflected. . The angle of deflection is changed by the power of the semiconductor laser 21 of the control light. When the power of the control light is zero, no deflection is performed, but the deflection angle increases as the power of the control light increases. The optical mixer 8 is used to adjust the optical paths of control light and signal light incident on the optical element 9. Any of a polarizing beam splitter, a non-polarizing beam splitter, or a dichroic mirror can be used.

The wavelength selection filter 10 cuts off the control light, transmits only the signal light, and deflects the signal light. As means for separating the signal light and the control light having different wavelengths from each other, a prism, a diffraction grating, a dichroic mirror, or the like can be used. As the wavelength selective transmission filter 10, if it is a wavelength selective transmission filter that can completely block light in the wavelength band of control light and efficiently transmit light in the wavelength band of signal light,
Any known one can be used.

[0069]

As described above, according to the present invention, an optical element capable of accurately deflecting light (signal light) transmitted through the element to a desired deflection angle by the refractive index distribution in the element. Can be provided.

Further, according to the present invention, since only the desired area of the optical element is heated in a short time because it is heated with light, it is easy to increase the frequency of the refractive index change. Therefore, 1
An optical element capable of controlling deflection at a high deflection frequency of about 0 kHz to 1 MHz can be provided. The required optical power is as low as about 20 to 130 mW, and the deflection angle in the range of 0 ° to 30 ° can be freely changed. These values correspond to the optical element 9
The above is a case where light is irradiated to a size of about 0.1 mm square. If the light irradiation area is set to about 0.03 mm square, a required power of about 2 to 13 mW is sufficient.

Further, according to the present invention, an inexpensive and highly accurate deflection element can be provided. This polarizing element is capable of a high deflection frequency of about 10 kHz to 1 MHz.

Further, according to the present invention, simply and accurately, 0
It is possible to provide a light control method capable of deflecting light at a deflection angle in the range of ゜ to 30 °. According to this light control method, a high deflection frequency of about 10 kHz to 1 MHz is possible, and the optical power required for deflection control is 20
Since a low optical power of about 130 mW is sufficient, a more energy-saving and more economical light control method can be provided.

Further, according to the present invention, it is possible to provide a light control device which has a simple device configuration, is inexpensive, and can accurately deflect light. This light control device has 10
A high deflection frequency of about kHz to 1 MHz is possible, and a large amount of information can be processed when applied to optical communication and optical information processing. The optical power required for the deflection control is, for example, a low optical power of about 20 to 130 mW is sufficient, and the running cost can be reduced. Further, the light control device can freely change the deflection angle in the range of 0 ° to 30 °.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a light control device when a gas laser or a solid-state laser according to a first embodiment of the present invention is used as control light.

FIG. 2 is a diagram showing the light intensity of control light incident on an optical element.

3A is a diagram illustrating an intensity distribution of laser light as control light, and FIG. 3B is a diagram illustrating a positional relationship between the intensity distribution of the laser light and a laser light transmission window. is there.

FIG. 4 is a diagram illustrating a configuration of a light control device when a semiconductor laser according to a second embodiment of the present invention is used as control light.

[Explanation of symbols]

 Reference Signs List 3 light modulator 4 shutter 5 lens group 6 ND filter 7 lens 8 optical mixer 9 optical element of present invention 10 wavelength selection filter 11 light source of control light (gas laser or solid laser) 12 light source of signal light (gas laser or solid laser) Reference Signs List 21 light source for control light (semiconductor laser) 22 light source for signal light (semiconductor laser) 51, 52 cylindrical lens 62 beam diameter 63 laser light transmission window

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koji Tsujida 3-12 Moriyacho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture Inside of Victor Company of Japan, Ltd. (72) Inventor Norio Tanaka 1-9-4 Horinouchi, Adachi-ku, Tokyo Dainichi Seika Industry Co., Ltd.

Claims (5)

[Claims] 1. An optical element comprising a photoresponsive composition configured to form a wedge-shaped refractive index distribution therein by being irradiated with light having a wedge-shaped light intensity distribution. 2. An optical element comprising a photoresponsive composition, and intensity distribution adjusting means for irradiating the optical element with light with a wedge-shaped light intensity distribution, wherein the optical element is controlled by control light. A deflection element using an optical element, wherein a refractive index distribution is formed, and signal light having a wavelength different from that of the control light is deflected by the refractive index distribution. 3. irradiating an optical element made of a photoresponsive composition with control light having a wavelength absorbed by the optical element while having a wedge-shaped light intensity distribution; and wedge-shaped in the optical element by the irradiation. Forming a refractive index distribution, and irradiating the optical element having the wedge-shaped refractive index distribution with signal light having a wavelength different from that of the control light, and controlling the light by deflecting the signal light. And a light control method using an optical element configured at least. 4. The light control method using an optical element according to claim 2, wherein the deflection angle of the deflection is changed by changing the intensity of the control light. 5. A deflecting element comprising at least an optical element made of a photoresponsive composition, and an intensity distribution adjusting means for irradiating the optical element with light having a wedge-shaped light intensity distribution, and the optical element absorbs light. A first light source that outputs light of a wavelength, and a second light source that outputs light of a different wavelength from the first light source, wherein wedges are formed in the optical element by the light of the first light source. A light control device using an optical element, wherein the light control device generates a shape-like refractive index distribution and controls the deflection of light of the second light source by the wedge-like refractive index distribution.