Stokes polarization measurement system and device based on corner reflector

Abstract

The utility model relates to a Stokes polarization measurement system and device based on a corner reflector, comprising a to-be-measured field adjusting unit and an interference unit, the to-be-measured field adjusting unit comprises a laser, a polarizer and a wave plate group; the polarizer and the wave plate group are arranged on a light path of the laser, the polarizer is arranged at a light outlet of the laser, and the wave plate group is arranged on one side, far away from the laser, of the polarizer; the interference unit comprises a beam splitter, a corner reflector, a plane mirror and a detector; the beam splitter and the corner reflector are arranged on a light path of the laser, the beam splitter is arranged on one side, far away from the polarizer, of the wave plate group, and the corner reflector is arranged on one side, far away from the wave plate group, of the beam splitter; the plane mirror is arranged at the other light outlet of the beam splitter, the detector is arranged right opposite to the plane mirror, and the detector is arranged on the side, away from the plane mirror, of the beam splitter. According to the utility model, the laser beam is divided into six equal areas at one time, and all Stokes parameters are calculated at one time, so that the polarization state of the laser beam is known.

Description

Technical Field

[0001] The utility model relates to the technical field of photoelectric detection, in particular to a Stokes polarization measurement system and equipment based on a corner reflector. Background Art

[0002] Although the traditional time-series polarization imaging has a simple structure, it cannot obtain all Stokes parameters at the same time. The commonly used Stokes polarimetry test requires at least four deterministic measurements in sequence to determine the Stokes parameters and has poor adaptability to moving targets. In many application scenarios, the characterized field changes rapidly over time, so one-time measurement technology is crucial to the accuracy of the characterization. One-time measurement technology involves many different ways of dividing the field amplitude, dividing the aperture, and dividing the focal plane, but all of them require simultaneous polarization measurements of all replicated fields after division to obtain multiple polarization parameters at one time. However, these methods require the analyzer to greatly reduce the energy, making the polarization analysis of weak signals less effective and relatively complex in the actual equipment construction, and difficult to implement in the process. Utility Model Content

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defect in the prior art that the polarization imaging structure is difficult to obtain multiple polarization parameters at one time.

[0004] In order to solve the above technical problems, the utility model provides a Stokes polarization measurement system based on a corner reflector, comprising:

[0005] A field adjustment unit to be measured, the field adjustment unit to be measured comprising a laser, a polarizer and a wave plate group; the polarizer and the wave plate group are arranged on the optical path of the laser, and the polarizer is arranged at the light outlet of the laser, and the wave plate group is arranged on the side of the polarizer away from the laser;

[0006] An interference unit, the interference unit comprises a beam splitter, a corner reflector, a plane reflector and a detector; the beam splitter and the corner reflector are arranged on the optical path of the laser, the beam splitter is arranged on the side of the wave plate group away from the polarizer, and the corner reflector is arranged on the side of the beam splitter away from the wave plate group; the plane reflector is arranged at the other light outlet of the beam splitter, the detector is arranged opposite to the plane reflector, and the detector is arranged on the side of the beam splitter away from the plane reflector.

[0007] In one embodiment of the present invention, a spatial filter is arranged between the polarizer and the wave plate group.

[0008] In one embodiment of the present invention, a first lens and a second lens are respectively disposed on both sides of the spatial filter, and the spatial filter is disposed at the focal point of the first lens and the second lens.

[0009] In one embodiment of the present invention, surfaces of the polarizer, the spatial filter, the first lens, the second lens and the wave plate group are all arranged perpendicular to the optical path of the laser.

[0010] In one embodiment of the present invention, the wave plate group includes a half-wave plate and a quarter-wave plate, and the half-wave plate is arranged parallel to the quarter-wave plate.

[0011] In one embodiment of the present invention, a third lens is arranged between the detector and the beam splitter.

[0012] In one embodiment of the present invention, the surface of the third lens is arranged parallel to the light outlet of the beam splitter.

[0013] In one embodiment of the present invention, the surface of the plane reflector is arranged parallel to the light outlet of the beam splitter.

[0014] A Stokes polarization measurement device based on a corner reflector comprises the Stokes polarization measurement system based on a corner reflector.

[0015] The above technical solution of the utility model has the following advantages compared with the prior art:

[0016] The utility model discloses a Stokes polarization measurement system and device based on a corner reflector. By using the corner reflector in an interferometer instead of a plane mirror, a novel Stokes polarization measurement system is designed. The laser beam is divided into six equal regions at one time, and all Stokes parameters are calculated at one time, thereby obtaining its polarization state. The utility model is suitable for one-time low-illuminance applications and time-varying polarization, and is low-cost and easy to implement in process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to make the content of the utility model easier to understand, the utility model is further described in detail according to the specific embodiments of the utility model in combination with the accompanying drawings, wherein

[0018] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0019] Explanation of the reference numerals in the specification: 1. laser; 2. polarizer; 3. first lens; 4. spatial filter; 5. second lens; 6. half-wave plate; 7. quarter-wave plate; 8. beam splitter; 9. corner reflector; 10. plane mirror; 11. third lens; 12. detector. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0021] Embodiment 1

[0022] Reference Figure 1 As shown, the utility model discloses a Stokes polarization measurement system based on a corner reflector, comprising:

[0023] A field adjustment unit to be measured, the field adjustment unit to be measured comprising a laser 1, a polarizer 2 and a wave plate group; the polarizer 2 and the wave plate group are arranged on the optical path of the laser 1, and the polarizer 2 is arranged at the light outlet of the laser 1, and the wave plate group is arranged on the side of the polarizer 2 away from the laser 1;

[0024] An interference unit, the interference unit includes a beam splitter 8, a corner reflector 9, a plane reflector 10 and a detector 12; the beam splitter 8 and the corner reflector 9 are arranged on the optical path of the laser 1, the beam splitter 8 is arranged on the side of the wave plate group away from the polarizer 2, and the corner reflector 9 is arranged on the side of the beam splitter 8 away from the wave plate group; the plane reflector 10 is arranged at the other light outlet of the beam splitter 8, the detector 12 is arranged opposite to the plane reflector 10, and the detector 12 is arranged on the side of the beam splitter 8 away from the plane reflector 10.

[0025] It can be imagined that the laser 1 in the field adjustment unit to be measured is used to emit laser beams of different wavelengths, and the polarizer 2 is used to polarize the laser beam to form polarized light. The target state for adjusting the polarized light is controlled by the wave plate group, and the amplitude of the incident field is adjusted at the same time. The incident field needs to have a limited size so that the energy of multiple parts can be detected. The beam splitter 8 in the interference unit is used to separate the light beam passing through the beam splitter 8 into two beams. One beam passes through the beam splitter 8 and then hits the corner reflector 9 and is returned by the corner reflector 9. The corner reflector 9 has the property of automatic collimation. When a beam of polarized light is incident on the vertex of the corner cube prism, the reflected light will be divided into six blocks and the polarization state of each area is different, which is very convenient to realize the one-time six-equal area division. The other beam of light is reflected by the beam splitter 8 and then reflected again by the plane reflector 10. Since the optical path through the corner reflector 9 is equal to twice the length of the corner reflector 9 itself, the position of the plane reflector 10 needs to be adjusted accordingly. When the two beams of reflected light converge again, interference occurs and is received by the detector 12. The detector 12 will image interference fringes in six different regions at once, and all Stokes parameters can be calculated at once without being constrained by timing, thereby obtaining its polarization state. If the input field changes in time, as long as the dynamic speed does not exceed the time resolution of the detector 12, it will be sufficient.

[0026] The utility model uses the corner reflector 9 in the interferometer instead of the plane mirror, designs a novel Stokes polarization measurement system, divides the laser beam into six equal regions at one time, calculates all the Stokes parameters at one time, and then knows its polarization state. The utility model is suitable for one-time low-illuminance application and time-varying polarization, and has low cost and easy process implementation.

[0027] Furthermore, a spatial filter 4 is provided between the polarizer 2 and the wave plate group.

[0028] Specifically, after passing through the spatial filter 4, the laser beam is constrained to be linearly polarized light with a Gaussian beam waist spot, thereby improving the quality of the laser beam.

[0029] Furthermore, a first lens 3 and a second lens 5 are respectively disposed on both sides of the spatial filter 4 , and the spatial filter 4 is disposed at the focal points of the first lens 3 and the second lens 5 .

[0030] Specifically, the first lens 3 is a condenser lens, which is arranged before the spatial filter 4 and focuses the light beam before entering the spatial filter 4 ; the second lens 5 is a collimator lens and collimates the light beam passing through the spatial filter 4 .

[0031] As a preferred solution of the utility model, the surfaces of the polarizer 2, the spatial filter 4, the first lens 3, the second lens 5 and the wave plate group are all arranged perpendicular to the optical path of the laser 1. And the polarizer 2, the spatial filter 4, the first lens 3, the second lens 5 and the wave plate group are coaxially arranged.

[0032] Furthermore, the wave plate group includes a half-wave plate 6 and a quarter-wave plate 7 , and the half-wave plate 6 is arranged parallel to the quarter-wave plate 7 .

[0033] Specifically, the combination of half-wave plate 6 and quarter-wave plate 7 is controlled to adjust the target state of polarized light. After the light beam is collimated, it is incident on the wave plate. The half-wave plate 6 and quarter-wave plate 7 are mounted on a rotating bracket controlled by a resonant piezoelectric motor. Different polarization states are created by rotating the combination of the two wave plates, and the amplitude of the incident field is adjusted at the same time.

[0034] Furthermore, a third lens 11 is arranged between the detector 12 and the beam splitter 8 .

[0035] Specifically, the third lens 11 is a collimating lens, which collimates the light beam reflected by the plane mirror and the light beam reflected by the corner reflector 9 and then injects them into the detector 12 for analysis. As a preferred solution of the utility model, the surface of the third lens 11 is arranged parallel to the light outlet of the beam splitter 8. And the surface of the plane reflector 10 is arranged parallel to the light outlet of the beam splitter 8.

[0036] Embodiment 2

[0037] A Stokes polarization measurement device based on a corner reflector includes the Stokes polarization measurement system based on a corner reflector described in the first embodiment.

[0038] In summary, the utility model introduces a Stokes polarization measurement system and device based on a corner reflector. By using the corner reflector 9 in an interferometer instead of a plane mirror, a novel Stokes polarization measurement system is designed, which divides the laser beam into six equal regions at one time, calculates all Stokes parameters at one time, and then knows its polarization state. The utility model is suitable for one-time low-illuminance applications and time-varying polarization, and is low-cost and easy to implement in process.

[0039] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention of the utility model.

Claims

1. A Stokes polarization measurement system based on a corner reflector, characterized in that: include: A field adjustment unit to be measured, the field adjustment unit to be measured comprising a laser, a polarizer and a wave plate group; the polarizer and the wave plate group are arranged on the optical path of the laser, and the polarizer is arranged at the light outlet of the laser, and the wave plate group is arranged on the side of the polarizer away from the laser; An interference unit, the interference unit comprises a beam splitter, a corner reflector, a plane reflector and a detector; the beam splitter and the corner reflector are arranged on the optical path of the laser, the beam splitter is arranged on the side of the wave plate group away from the polarizer, and the corner reflector is arranged on the side of the beam splitter away from the wave plate group; the plane reflector is arranged at the other light outlet of the beam splitter, the detector is arranged opposite to the plane reflector, and the detector is arranged on the side of the beam splitter away from the plane reflector.

2. The Stokes polarization measurement system based on corner reflector according to claim 1, characterized in that: A spatial filter is arranged between the polarizer and the wave plate group.

3. The Stokes polarization measurement system based on corner reflector according to claim 2, characterized in that: A first lens and a second lens are respectively disposed on both sides of the spatial filter, and the spatial filter is disposed at the focal points of the first lens and the second lens.

4. The Stokes polarization measurement system based on corner reflector according to claim 3, characterized in that: The surfaces of the polarizer, the spatial filter, the first lens, the second lens and the wave plate group are all arranged perpendicular to the optical path of the laser.

5. The Stokes polarization measurement system based on corner reflector according to claim 1, characterized in that: The wave plate group includes a half-wave plate and a quarter-wave plate, and the half-wave plate is arranged parallel to the quarter-wave plate.

6. The Stokes polarization measurement system based on corner reflector according to claim 1, characterized in that: A third lens is arranged between the detector and the beam splitter.

7. The Stokes polarization measurement system based on corner reflector according to claim 6, characterized in that: The surface of the third lens is arranged parallel to the light outlet of the beam splitter.

8. The Stokes polarization measurement system based on corner reflector according to claim 1, characterized in that: The surface of the plane reflector is arranged parallel to the light outlet of the beam splitter.

9. A Stokes polarization measurement device based on a corner reflector, characterized in that: A Stokes polarization measurement system based on a corner reflector comprising the system as claimed in any one of claims 1 to 8.

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