CN113495374A - Method and system for improving diffraction efficiency of acousto-optic tunable filter - Google Patents
Method and system for improving diffraction efficiency of acousto-optic tunable filter Download PDFInfo
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- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/11—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on acousto-optical elements, e.g. using variable diffraction by sound or like mechanical waves
- G02F1/116—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on acousto-optical elements, e.g. using variable diffraction by sound or like mechanical waves using an optically anisotropic medium, wherein the incident and the diffracted light waves have different polarizations, e.g. acousto-optic tunable filter [AOTF]
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Abstract
The invention relates to a method and a system for improving diffraction efficiency, in particular to a method and a system for improving diffraction efficiency of an acousto-optic tunable filter, which solve the problems that the intensity of incident light energy from a target is reduced by half due to the addition of a front-mounted polarizing device, further, the diffraction efficiency of the acousto-optic tunable filter is reduced by half, and the measurement is not facilitated under the condition of weak light. The method is characterized in that: step 1: splitting natural or unpolarized incident light from a target into transmitted light and reflected light; step 2: carrying out linear polarization treatment on the reflected light; then, reversing the light path to enable the direction of the light path to be parallel to the direction of the light path of the transmitted light obtained in the step 1; then, phase delay is carried out, so that the phase of the phase is consistent with that of the transmitted light obtained in the step 1; and step 3: combining the transmitted light obtained in the step 1 with the reflected light after phase delay in the step 2; and 4, step 4: the combined beam light and the ultrasonic wave interact in the acousto-optic tunable filter to output diffracted light.
Description
Technical Field
The invention relates to a method and a system for improving diffraction efficiency, in particular to a method and a system for improving diffraction efficiency of an acousto-optic tunable filter.
Background
The acousto-optic tunable filter is a novel light splitting element in which ultrasonic waves and light waves can generate acousto-optic effect in an anisotropic medium. The acousto-optic tunable filter mainly comprises an acousto-optic medium, a piezoelectric transducer, an absorber and an ultrasonic frequency driver. The ultrasonic frequency driver transmits an ultrasonic signal with a certain frequency, the ultrasonic signal is input into an acousto-optic medium through the piezoelectric transducer, an ultrasonic grating is further formed in the acousto-optic medium, and when an incident light wave and the ultrasonic wave meet a momentum matching condition, a nonlinear effect is generated in the acousto-optic medium to generate a diffraction light wave; the process is equivalent to the process that the incident light wave is diffracted into narrow-band diffracted light after passing through the ultrasonic grating; the process that the broadband light source is selected to be light with single wavelength after passing through the light splitting and dispersing element of the acousto-optic tunable filter can also be explained; in general, we refer to this process as acousto-optic modulation. Compared with the traditional light splitting device, the solid band-pass acousto-optic tunable filter has incomparable unique advantages, and specifically comprises the following components:
(1) the wavelength tuning is stable, reliable and wide in range;
(2) the switching speed of the diffraction spectrum output wavelength is high, and is usually only a few microseconds;
(3) a very high extinction ratio can be obtained;
(4) the working mode is flexible and various, has the modes of single-point scanning, continuous scanning, random scanning, multi-point scanning and the like, and is very suitable for working in the fields of multispectral imaging and hyperspectral imaging;
(5) the output of parameters such as wavelength or intensity of the diffracted light can be selected by utilizing a computer to control the electric signal;
(6) the imaging device has larger incident light angle aperture and output aperture, and is very suitable for being applied to imaging;
(7) the whole weight is light, the volume is small, all elements are solid structures, no moving parts are provided, the anti-interference capability is strong, and the device is suitable for being applied to airborne systems, satellite-borne systems and other systems;
(8) the light flux is large, and the spectral resolution and the diffraction efficiency of the diffracted light in the tuning range are high;
(9) the power consumption is very low, typically less than 2W.
Therefore, the acousto-optic tunable filter has a very large application potential in many optical researches, especially in the fields of life science and aerospace. Particularly, the wavelength tuning range of the acousto-optic tunable filter can be from an ultraviolet band to a long-wave infrared region, and the wavelength switching speed is fast, so that the new momentum of the acousto-optic tunable filter as a light splitting element is developed at a high speed in recent decades, and the acousto-optic tunable filter becomes an indispensable core device in spectral imaging application.
In both the acousto-optic tunable filter designed collinearly and the acousto-optic tunable filter designed non-collinearly, the incident light interacting with the ultrasonic wave in the acousto-optic medium must be polarized light, that is, the natural light or the non-polarized incident light beam must pass through the polarizer before entering the acousto-optic tunable filter to form the polarized light interacting with the ultrasonic wave in the acousto-optic medium. In practical applications, for example, when a far-field target is subjected to spectrum collection or imaging, a polarization device needs to be added at the front end of the acousto-optic tunable filter to form polarized light from reflected light, radiated light or transmitted light of the target, otherwise, diffracted light and 0-order transmitted light are easily overlapped at the tail end of the system, and the accuracy of the collection result is further affected. However, the addition of the pre-polarizer inevitably causes the energy intensity of the natural light or unpolarized incident light from the target to be reduced by half, so the diffraction efficiency of the acousto-optic tunable filter is also reduced by half correspondingly, and if the acousto-optic tunable filter is under the condition of weak light, the experimental measurement is very unfavorable.
Disclosure of Invention
The invention aims to provide a method and a system for improving the diffraction efficiency of an acousto-optic tunable filter, which aim to solve the technical problems that the energy intensity of natural light or non-polarized incident light from a target is reduced by half due to the addition of a front-arranged polarizing device, the diffraction efficiency of the acousto-optic tunable filter is correspondingly reduced by half, and experimental measurement is not facilitated under the condition of weak light.
The technical scheme adopted by the invention is that the method for improving the diffraction efficiency of the acousto-optic tunable filter is characterized by comprising the following steps of:
step 1: splitting natural or unpolarized incident light from a target into transmitted light and reflected light; the polarization direction of the transmitted light is required to be consistent with the polarization direction of the incident light of the acousto-optic tunable filter;
step 2: performing linear polarization treatment on the reflected light obtained in the step 1 to improve the extinction ratio and enable the polarization direction of the reflected light to be vertical to the polarization direction of the transmitted light obtained in the step 1; then, reversing the light path to enable the direction of the light path to be parallel to the direction of the light path of the transmitted light obtained in the step 1; then, phase delay is carried out to make the phase of the phase consistent with that of the transmitted light obtained in the step 1;
and step 3: combining the transmitted light obtained in the step 1 and the reflected light subjected to phase delay in the step 2 to obtain combined light;
and 4, step 4: and 3, interacting the beam combining light and the ultrasonic wave obtained in the step 3 in the acousto-optic tunable filter, and outputting diffracted light.
Further, in step 1, the natural light or unpolarized incident light from the target is split into transmitted light and reflected light, and the adopted optical device is a first polarization beam splitter;
the first polarization beam splitter is a polarization beam splitting cube prism.
Further, in step 2, the optical device for performing linear polarization processing is a linear polarizer.
Further, in step 2, the optical device used for reversing the optical path is an optical path reversing unit;
the light path reversing unit comprises a first reflecting mirror, a second reflecting mirror and a second polarization beam splitter;
the first reflector is arranged on an emergent light path of the linear polaroid, a reflecting surface of the first reflector faces the linear polaroid, and an included angle between the reflecting surface of the first reflector and the emergent light of the linear polaroid is not equal to 90 degrees;
the second reflecting mirror is arranged on the emergent light path of the first reflecting mirror; the second reflector and the first reflector are arranged vertically, and the reflecting surfaces of the second reflector and the first reflector are arranged oppositely;
the second polarization beam splitter is arranged on an emergent light path of the second reflecting mirror, and a reflection light path of the second polarization beam splitter is in the same direction as a transmission light path of the first polarization beam splitter; the second polarization beam splitter is a polarization beam splitting cube prism.
Further, in step 2, the optical device for performing phase delay is a phase modulation device;
the phase adjusting device is a liquid crystal phase variable retarder or a broadband achromatic wave plate.
Further, in step 3, the transmitted light obtained in step 1 and the reflected light after phase delay in step 2 are combined, and the adopted optical device is a light beam combining unit;
the light beam combining unit is in a binocular beam combining form formed by lenses or in a 2 x 1 optical fiber coupling form.
The invention also provides a system for improving the diffraction efficiency of the acousto-optic tunable filter, which comprises the acousto-optic tunable filter and a polarization unit arranged at the front end of the acousto-optic tunable filter; it is characterized in that:
the polarization unit comprises a first polarization beam splitter, a linear polarizer, a light path reversing unit, a phase modulation device and a light beam combining unit;
the first polarization beam splitter is used for receiving natural light or non-polarized incident light from a target and splitting the incident light into transmitted light and reflected light, and the polarization direction of the transmitted light is consistent with the polarization direction of the incident light of the acousto-optic tunable filter; the first polarization beam splitter is a polarization beam splitting cubic prism;
the linear polaroid and the light path reversing unit are sequentially arranged on a reflection light path of the first polarization beam splitter from near to far; the light path reversing unit is used for enabling the light path direction of the reflected light after linear polarization treatment of the warp polarizing film to be parallel to the light path direction of the transmitted light obtained after beam splitting of the first polarization beam splitter;
the phase modulation device is arranged on an emergent light path of the light path reversing unit;
the light beam combining unit is used for combining the transmitted light split by the first polarization beam splitter and the reflected light subjected to phase modulation by the phase modulation device;
the acousto-optic tunable filter is arranged on an emergent light path of the light beam combining unit.
Further, the phase adjusting device is a liquid crystal phase variable retarder or a broadband achromatic wave plate.
Further, the optical path reversing unit comprises a first reflecting mirror, a second reflecting mirror and a second polarization beam splitter;
the first reflector is arranged on an emergent light path of the linear polaroid, a reflecting surface of the first reflector faces the linear polaroid, and an included angle between the reflecting surface of the first reflector and the emergent light of the linear polaroid is not equal to 90 degrees;
the second reflecting mirror is arranged on the emergent light path of the first reflecting mirror; the second reflector and the first reflector are arranged vertically, and the reflecting surfaces of the second reflector and the first reflector are arranged oppositely;
the second polarization beam splitter is arranged on an emergent light path of the second reflecting mirror, and a reflection light path of the second polarization beam splitter is in the same direction as a transmission light path of the first polarization beam splitter; the second polarization beam splitter is a polarization beam splitting cube prism.
Further, the light beam combining unit is in a binocular beam combining form formed by lenses or in a 2 × 1 optical fiber coupling form.
The invention has the beneficial effects that:
(1) the invention relates to a method and a system for improving the diffraction efficiency of an acousto-optic tunable filter, which comprises the following steps of splitting natural light or non-polarized incident light from a target into transmitted light and reflected light; secondly, the extinction ratio of the reflected light is improved through linear polarization treatment; then, the phase of the reflected light is delayed to be consistent with that of the transmitted light, and the polarization directions of the reflected light and the transmitted light are the same; finally, beam combination is carried out; thus, the energy of the beam combining light is obviously larger than the energy remained after the natural light or the non-polarized incident light passes through the traditional polarizing device and the energy is lost by at least 50%; furthermore, the interaction between the beam combination light and the ultrasonic wave occurs in the acousto-optic tunable filter, and the efficiency of diffraction is correspondingly improved; therefore, the invention solves the technical problems that the energy intensity of natural light or non-polarized incident light from a target is reduced by half due to the addition of a front-arranged polarization device, the diffraction efficiency of an acousto-optic tunable filter is correspondingly reduced by half, and the experimental measurement is very unfavorable under the condition of weak light.
(2) The invention splits natural light or non-polarized incident light from a target into transmitted light and reflected light, and the adopted optical device is a first polarization beam splitter which is a polarization beam splitting cubic prism; thus, the extinction ratio of the transmitted light obtained by the beam splitting can be made high, and the extinction ratio of the reflected light can be made low.
(3) The optical device adopted for linear polarization treatment is a linear polarizer, and the linear polarizer is preferably a linear polarizer with a high extinction ratio, so that reflected light after linear polarization treatment can obtain a higher extinction ratio, and the final diffraction efficiency is further improved.
(4) The light path reversing unit preferably comprises a first reflector, a second reflector and a second polarization beam splitter; the second polarization beam splitter is a polarization beam splitting cubic prism; therefore, after the light path is reversed by the light path reversing unit, the extinction ratio of the reflected light emitted from the light path reversing unit is basically not reduced compared with the extinction ratio before the reflected light passes through the light path reversing unit, the high extinction ratio is still maintained, and the final diffraction efficiency can be further improved.
Drawings
FIG. 1 is a schematic structural diagram of an embodiment of a system for improving diffraction efficiency of an acousto-optic tunable filter according to the present invention.
The reference numerals in the drawings are explained as follows:
the device comprises a 1-first polarization beam splitter, a 2-second polarization beam splitter, a 3-linear polarizer, a 4-first reflector, a 5-second reflector, a 6-phase modulation device, a 7-beam combination unit, an 8-acousto-optic tunable filter, a 9-optical path reversing unit and a 10-polarization unit.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
The method for improving the diffraction efficiency of the acousto-optic tunable filter comprises the following steps:
step 1: splitting natural or unpolarized incident light from a target into transmitted light and reflected light; the polarization direction of the transmitted light is required to be consistent with the polarization direction of the incident light of the acousto-optic tunable filter; referring to fig. 1, in the present embodiment, natural light or unpolarized incident light from a target is split into transmitted light and reflected light, and the optical device used is a first polarization beam splitter 1; the first polarization beam splitter 1 is a polarization beam splitting cube prism, and thus, the extinction ratio of the transmitted light obtained by beam splitting can be made high and the extinction ratio of the reflected light can be made low.
Step 2: performing linear polarization treatment on the reflected light obtained in the step 1 to improve the extinction ratio and enable the polarization direction of the reflected light to be vertical to the polarization direction of the transmitted light obtained in the step 1; then, reversing the light path to enable the direction of the light path to be parallel to the direction of the light path of the transmitted light obtained in the step 1; then, phase delay is carried out to make the phase of the phase consistent with that of the transmitted light obtained in the step 1; referring to fig. 1, in the present embodiment, the optical device used for performing linear polarization processing is a linear polarizer 3; the ground polarizer 3 is preferably a high extinction ratio linear polarizer, thus ensuring that the reflected light possesses a higher extinction ratio. In this embodiment, the optical device used for reversing the optical path is an optical path reversing unit 9; preferably, the optical path reversing unit 9 includes a first mirror 4, a second mirror 5, and a second polarization beam splitter 2; the first reflector 4 is arranged on the emergent light path of the linear polaroid 3, the reflecting surface of the first reflector 4 faces the linear polaroid 3, and the included angle between the reflecting surface of the first reflector 4 and the emergent light of the linear polaroid 3 is not equal to 90 degrees; the second reflector 5 is arranged on the emergent light path of the first reflector 4; the second reflector 5 is perpendicular to the first reflector 4, and the reflecting surfaces of the second reflector and the first reflector are arranged oppositely; the second polarization beam splitter 2 is arranged on an emergent light path of the second reflecting mirror 5, and a reflection light path of the second polarization beam splitter 2 is in the same direction as a transmission light path of the first polarization beam splitter 1; the second polarizing beam splitter 2 is a polarizing beam splitting cube prism, so that the transmitted component of the reflected light can be transmitted, and the extinction ratio of the reflected light is higher. The second polarization beam splitter 2 in the above-described optical path reversing unit 9 may also be replaced with a mirror. In this embodiment, the optical device for performing phase delay is the phase modulation device 6; the phase modulation device 6 is preferably a liquid crystal phase variable retarder, and may be a phase modulation device capable of matching the phase of the reflected light with the phase of the transmitted light, such as a broadband achromatic plate, in addition to the liquid crystal phase variable retarder of the present embodiment.
And step 3: combining the transmitted light obtained in the step 1 and the reflected light subjected to phase delay in the step 2 to obtain combined light; referring to fig. 1, in the present embodiment, the optical device for combining is a light beam combining unit 7; in this embodiment, the light beam combining unit 7 is a binocular combining form composed of lenses, and may be other light beam combining units capable of realizing a beam combining function, such as a 2 × 1 fiber coupling form, besides the binocular combining form composed of lenses in this embodiment.
And 4, step 4: and 3, interacting the beam combining light and the ultrasonic wave obtained in the step 3 in the acousto-optic tunable filter, and outputting diffracted light.
Referring to fig. 1, the system for improving the diffraction efficiency of the acousto-optic tunable filter of the present invention includes an acousto-optic tunable filter 8 and a polarization unit 10 disposed at the front end thereof.
The polarization unit 10 includes a first polarization beam splitter 1, a linear polarizer 3, an optical path reversing unit 9, a phase modulation device 6, and a beam combining unit 7. The first polarization beam splitter 1 is used for receiving natural light or non-polarized incident light from a target and splitting the incident light into transmitted light and reflected light, and the polarization direction of the transmitted light is consistent with the polarization direction of the incident light of the acousto-optic tunable filter 8; the first polarization beam splitter 1 is a polarization beam splitting cubic prism; the linear polarizer 3 and the light path reversing unit 9 are sequentially arranged on the reflection light path of the first polarization beam splitter 1 from near to far; in the present embodiment, the ground polarizing plate 3 is preferably a linear polarizing plate having a high extinction ratio; the light path reversing unit 9 is configured to make the light path direction of the reflected light that is linearly polarized by the polarizing plate 3 parallel to the light path direction of the transmitted light obtained by splitting the beam by the first polarization beam splitter 1; in the present embodiment, it is preferable that the above-mentioned optical path reversing unit 9 includes the first reflecting mirror 4, the second reflecting mirror 5, and the second polarization beam splitter 2; the first reflector 4 is arranged on the emergent light path of the linear polaroid 3, the reflecting surface of the first reflector 4 faces the linear polaroid 3, and the included angle between the reflecting surface of the first reflector 4 and the emergent light of the linear polaroid 3 is not equal to 90 degrees; the second reflector 5 is arranged on the emergent light path of the first reflector 4; the second reflector 5 is perpendicular to the first reflector 4, and the reflecting surfaces of the second reflector and the first reflector are arranged oppositely; the second polarization beam splitter 2 is arranged on an emergent light path of the second reflecting mirror 5, and a reflection light path of the second polarization beam splitter 2 is in the same direction as a transmission light path of the first polarization beam splitter 1; the second polarizing beam splitter 2 is a polarizing beam splitting cube prism. The second polarization beam splitter 2 in the above-described optical path reversing unit 9 may also be replaced with a mirror. The phase modulation device 6 is arranged on an emergent light path of the light path reversing unit 9; in the present embodiment, the phase modulation device 6 is preferably a liquid crystal phase variable retarder, and may be a phase modulation device capable of matching the phase of the reflected light with the phase of the transmitted light, such as a broadband achromatic plate, in addition to the liquid crystal phase variable retarder of the present embodiment. The beam combining unit 7 is configured to combine the transmitted light split by the first polarization beam splitter 1 and the reflected light phase-modulated by the phase modulation device 6; in this embodiment, the light beam combining unit 7 is a binocular combining form composed of lenses, and may be other light beam combining units capable of realizing a beam combining function, such as a 2 × 1 fiber coupling form, besides the binocular combining form composed of lenses in this embodiment. The acousto-optic tunable filter 8 is disposed on the outgoing light path of the beam combining unit 7. The system for improving the diffraction efficiency of the acousto-optic tunable filter can output diffraction light with higher intensity and narrow spectrum bandwidth.
Claims (10)
1. A method for improving the diffraction efficiency of an acousto-optic tunable filter is characterized by comprising the following steps:
step 1: splitting natural or unpolarized incident light from a target into transmitted light and reflected light; the polarization direction of the transmitted light is required to be consistent with the polarization direction of the incident light of the acousto-optic tunable filter;
step 2: performing linear polarization treatment on the reflected light obtained in the step 1 to improve the extinction ratio and enable the polarization direction of the reflected light to be vertical to the polarization direction of the transmitted light obtained in the step 1; then, reversing the light path to enable the direction of the light path to be parallel to the direction of the light path of the transmitted light obtained in the step 1; then, phase delay is carried out to make the phase of the phase consistent with that of the transmitted light obtained in the step 1;
and step 3: combining the transmitted light obtained in the step 1 and the reflected light subjected to phase delay in the step 2 to obtain combined light;
and 4, step 4: and 3, interacting the beam combining light and the ultrasonic wave obtained in the step 3 in the acousto-optic tunable filter, and outputting diffracted light.
2. The method for improving the diffraction efficiency of an acousto-optic tunable filter according to claim 1, wherein:
in the step 1, the natural light or non-polarized incident light from the target is split into transmitted light and reflected light, and the adopted optical device is a first polarization beam splitter (1);
the first polarization beam splitter (1) is a polarization beam splitting cube prism.
3. The method of claim 2, wherein the step of increasing the diffraction efficiency of the acousto-optic tunable filter comprises: in the step 2, the optical device for linear polarization treatment is a linear polarizer (3).
4. The method for improving the diffraction efficiency of an acousto-optic tunable filter according to claim 3, wherein:
in the step 2, the optical device used for reversing the light path is a light path reversing unit (9);
the light path reversing unit (9) comprises a first reflecting mirror (4), a second reflecting mirror (5) and a second polarization beam splitter (2);
the first reflector (4) is arranged on an emergent light path of the linear polaroid (3), a reflecting surface of the first reflector (4) faces the linear polaroid (3), and an included angle formed by the first reflector and the emergent light of the linear polaroid (3) is not equal to 90 degrees;
the second reflector (5) is arranged on the emergent light path of the first reflector (4); the second reflector (5) and the first reflector (4) are arranged vertically, and the reflecting surfaces of the second reflector and the first reflector are arranged oppositely;
the second polarization beam splitter (2) is arranged on an emergent light path of the second reflecting mirror (5), and a reflection light path of the second polarization beam splitter (2) is in the same direction as a transmission light path of the first polarization beam splitter (1); the second polarization beam splitter (2) is a polarization beam splitting cube prism.
5. The method for improving the diffraction efficiency of an acousto-optic tunable filter according to any one of claims 1 to 4, wherein:
in the step 2, the optical device for phase delay is a phase modulation device (6);
the phase modulation device (6) is a liquid crystal phase variable retarder or a broadband achromatic wave plate.
6. The method of claim 5, wherein the step of increasing the diffraction efficiency of the acousto-optic tunable filter comprises:
in the step 3, the transmitted light obtained in the step 1 and the reflected light after the phase delay in the step 2 are combined, and an optical device adopted is a light beam combining unit (7);
the light beam combining unit (7) is in a binocular beam combining form formed by lenses or in a 2 x 1 optical fiber coupling form.
7. A system for improving the diffraction efficiency of an acousto-optic tunable filter comprises an acousto-optic tunable filter (8) and a polarization unit (10) arranged at the front end of the acousto-optic tunable filter; the method is characterized in that:
the polarization unit (10) comprises a first polarization beam splitter (1), a linear polarizer (3), an optical path reversing unit (9), a phase modulation device (6) and a light beam combining unit (7);
the first polarization beam splitter (1) is used for receiving natural light or non-polarized incident light from a target and splitting the incident light into transmitted light and reflected light, and the polarization direction of the transmitted light is consistent with the polarization direction of the incident light of the acousto-optic tunable filter (8); the first polarization beam splitter (1) is a polarization beam splitting cubic prism;
the linear polaroid (3) and the light path reversing unit (9) are sequentially arranged on a reflected light path of the first polarization beam splitter (1) from near to far; the light path reversing unit (9) is used for enabling the light path direction of the reflected light subjected to linear polarization treatment by the linear polarizer (3) to be parallel to the light path direction of the transmitted light obtained after beam splitting by the first polarization beam splitter (1);
the phase modulation device (6) is arranged on an emergent light path of the light path reversing unit (9);
the light beam combining unit (7) is used for combining the transmitted light split by the first polarization beam splitter (1) and the reflected light subjected to phase modulation by the phase modulation device (6);
the acousto-optic tunable filter (8) is arranged on an emergent light path of the light beam combining unit (7).
8. The system for improving the diffraction efficiency of an acousto-optic tunable filter according to claim 7, wherein: the phase modulation device (6) is a liquid crystal phase variable retarder or a broadband achromatic wave plate.
9. The system for improving the diffraction efficiency of an acousto-optic tunable filter according to claim 7 or 8, wherein:
the light path reversing unit (9) comprises a first reflecting mirror (4), a second reflecting mirror (5) and a second polarization beam splitter (2);
the first reflector (4) is arranged on an emergent light path of the linear polaroid (3), a reflecting surface of the first reflector (4) faces the linear polaroid (3), and an included angle formed by the first reflector and the emergent light of the linear polaroid (3) is not equal to 90 degrees;
the second reflector (5) is arranged on the emergent light path of the first reflector (4); the second reflector (5) and the first reflector (4) are arranged vertically, and the reflecting surfaces of the second reflector and the first reflector are arranged oppositely;
the second polarization beam splitter (2) is arranged on an emergent light path of the second reflecting mirror (5), and a reflection light path of the second polarization beam splitter (2) is in the same direction as a transmission light path of the first polarization beam splitter (1); the second polarization beam splitter (2) is a polarization beam splitting cube prism.
10. The system for improving the diffraction efficiency of an acousto-optic tunable filter according to claim 9, wherein: the light beam combining unit (7) is in a binocular beam combining form formed by lenses or in a 2 x 1 optical fiber coupling form.
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| CN2178906Y (en) * | 1993-10-16 | 1994-10-05 | 中国大恒公司 | Broad band light polarization state function table |
| US20080088815A1 (en) * | 2006-10-16 | 2008-04-17 | Hiroshi Nomura | Polarization optical system |
| CN101377571A (en) * | 2007-08-28 | 2009-03-04 | 鸿富锦精密工业（深圳）有限公司 | Stereo projection optical system |
| CN102375247A (en) * | 2011-10-26 | 2012-03-14 | 福建福晶科技股份有限公司 | Polarized coupling system |
| CN103370651A (en) * | 2010-12-10 | 2013-10-23 | Nkt光子学有限公司 | An acousto-optical tunable filter (AOTF) for a broad band source for fluorescence measurement system |
| CN104503099A (en) * | 2015-01-09 | 2015-04-08 | 中国人民解放军国防科学技术大学 | Light polarization compensation device based on beam shaping technology and space beam combination system |
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2020
- 2020-03-20 CN CN202010200995.1A patent/CN113495374A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2178906Y (en) * | 1993-10-16 | 1994-10-05 | 中国大恒公司 | Broad band light polarization state function table |
| US20080088815A1 (en) * | 2006-10-16 | 2008-04-17 | Hiroshi Nomura | Polarization optical system |
| CN101377571A (en) * | 2007-08-28 | 2009-03-04 | 鸿富锦精密工业（深圳）有限公司 | Stereo projection optical system |
| CN103370651A (en) * | 2010-12-10 | 2013-10-23 | Nkt光子学有限公司 | An acousto-optical tunable filter (AOTF) for a broad band source for fluorescence measurement system |
| CN102375247A (en) * | 2011-10-26 | 2012-03-14 | 福建福晶科技股份有限公司 | Polarized coupling system |
| CN104503099A (en) * | 2015-01-09 | 2015-04-08 | 中国人民解放军国防科学技术大学 | Light polarization compensation device based on beam shaping technology and space beam combination system |
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