A high-precision controllable medium-long wave infrared polarization degree radiation source

Abstract

The present application relates to a kind of high-precision controllable middle-long wave infrared polarization degree radiation source, including carbon silicon rod infrared source, aperture diaphragm, infrared integrating sphere, collimator and polarization degree adjusting module, four infrared optical flat of polarization degree adjusting module is located between the light inlet hole and light outlet hole of adjusting cavity, and is divided into two groups, two infrared optical flat in each group is arranged in parallel interval, infrared optical flat is symmetrically arranged between the front and rear two groups along vertical direction, and the linearly polarized light of the corresponding polarization degree with the angle of incidence is output from light outlet hole, and the output shaft of servo motor is connected with the side middle part of each infrared optical flat installed on support, the inclination angle of infrared optical flat is adjusted. The influence of its own thermal radiation is eliminated by filling into refrigeration inert gas. The radiation source is simple in structure, portable, convenient to adjust, improves the precision and dynamic range of the output linear polarization degree of infrared polarization degree radiation source, meets the need of space field test.

Description

Technical Field

[0001] This invention relates to the field of optical detection technology, and in particular to a high-precision controllable medium- and long-wave infrared polarization radiation source. Background Technology

[0002] Infrared polarization detection typically obtains the target's polarization state by measuring the intensity of reflected or spontaneously emitted light from the target surface. This polarization information is then interpreted to invert the target's properties and state. To accurately obtain the target's polarization information, high-precision polarization calibration of infrared polarization optical instruments is required to correct or eliminate polarization signals generated by the remote sensor itself.

[0003] Infrared polarization calibration is primarily used for quantitative applications in polarization optics instruments. Its purpose is to determine the quantitative relationship between the final output of an infrared polarization system and a known incident polarization radiation reference. Theoretically, the polarization response characteristics of a remote sensor can be completely and quantitatively described using a Muller matrix, while the polarization state of the calibration reference light source can be represented by Stokes parameters. Therefore, the main technical content of polarization calibration is to input a standard polarization light source with a known polarization signal into the remote sensor and verify the polarization calibration results by solving for the Muller matrix of the remote sensor based on its output. Therefore, achieving polarization radiation calibration of an infrared polarization imaging system requires a high-precision and adjustable infrared polarization radiation source. This is especially true when applied in aerospace-related fields, where even higher precision is required.

[0004] Currently, commonly used infrared polarization radiation calibration sources are mainly divided into three categories: The first category utilizes linear polarizers and unpolarized radiation sources (blackbody) to generate polarized radiation with different polarization states. However, the polarizers in this type of infrared polarization radiation source are affected by their own radiation and the radiation from the surrounding environment, making it difficult to obtain a high degree of polarization. The second category is reflective infrared polarization radiation sources, which utilize the reflection of infrared radiation incident on two different medium surfaces, thus producing a polarization phenomenon. Different polarized light can be generated by adjusting the incident angle of the radiation. However, in practical applications, since the angle of reflected radiation also changes with the incident angle, the observation angle needs to be considered, making it inconvenient to use. The third category is transmissive infrared polarization radiation sources, which utilize the polarization effect caused by multiple reflections and refractions of infrared radiation on the medium surface, thereby producing infrared radiation with different degrees of linear polarization. Among these, transmissive infrared polarization radiation sources are widely used in the polarization calibration of infrared polarization measurement equipment due to their large dynamic range of output polarization degree, high parallelism, and relatively high polarization degree output accuracy. However, the maximum polarization degree output of existing transmissive infrared polarization radiation sources is only 0.48. For targets with strong reflectivity, such as aluminum, the infrared polarization degree may exceed 0.48 at certain observation angles. The dynamic range of polarization degree adjustment of existing transmissive infrared polarization radiation sources is insufficient, making it difficult to meet testing requirements. Moreover, the accuracy of the output infrared polarization degree is reduced due to the influence of the reactor's own thermal radiation. Summary of the Invention

[0005] The purpose of this invention is to provide a high-precision controllable mid-to-long-wave infrared polarization radiation source with a wide dynamic range and continuously adjustable infrared polarization, while improving the dynamic range and accuracy of polarization adjustment of the infrared polarization radiation source.

[0006] To achieve the above objectives, the present invention provides a high-precision controllable medium- and long-wave infrared polarization radiation source, comprising a silicon carbide rod infrared source, an aperture stop, an infrared integrating sphere, a collimator, and a polarization adjustment module. The silicon carbide rod infrared source can emit medium- and long-wave infrared radiation light sources, which are incident into the infrared integrating sphere after passing through the aperture stop, and output high-brightness unpolarized radiation light waves. The collimator is set in the output optical path of the infrared integrating sphere to collimate the radiation light waves.

[0007] The polarization adjustment module includes an adjustment cavity and four infrared optical plates. One end of the adjustment cavity has an entrance hole, which is located on the output light path of the collimator. The other end has an exit hole. The four infrared optical plates are located between the entrance hole and the exit hole and are divided into two groups along the direction from the entrance hole to the exit hole. The first two infrared optical plates form one group, and the last two infrared optical plates form another group. The two infrared optical plates in each group are arranged in parallel and spaced apart. The two groups of infrared optical plates are symmetrically arranged in the vertical direction. The radiation light wave output by the collimator passes through the four infrared optical plates in sequence and is output from the exit hole as linearly polarized light with a polarization degree corresponding to the incident angle. Each infrared optical plate is mounted on a bracket, which is connected to the output shaft of a servo motor and can rotate synchronously with the output shaft to adjust the tilt angle of the infrared optical plate. The connection between the output shaft and the bracket is located on the side of the bracket and in the middle of the vertical direction.

[0008] The inside of the regulating chamber is blackened, and the regulating chamber is also equipped with a gas inlet for filling in inert gas for cooling.

[0009] Optionally, the servo motor is located outside the adjustment cavity, and one end of the output shaft extends into the adjustment cavity and is connected to the bracket.

[0010] Optionally, the output shaft is also connected to an angle sensor for real-time measurement of the rotation angle of the infrared optical plate. The angle sensor is located outside the adjustment cavity.

[0011] Optionally, the effective light transmission diameters of the entrance aperture and the exit aperture are the same and larger than the effective light transmission diameter of the collimator.

[0012] Optionally, the tilt angle of the infrared optical plate ranges from 0° to 60°.

[0013] Optionally, the interval between the two infrared optical plates in each group is smaller than the interval between the two groups of infrared optical plates.

[0014] Optionally, the infrared optical flat panel is a single-crystal silicon wafer.

[0015] Optionally, the inert gas used for refrigeration is liquid nitrogen.

[0016] Optionally, a transparent sheet is provided at the light inlet and light outlet for passing through the radiated light waves, and the two transparent sheets seal the light inlet and light outlet respectively.

[0017] The above-mentioned technical solution of the present invention has the following advantages: The high-precision controllable medium- and long-wave infrared polarization radiation source provided by the present invention includes a silicon carbide rod infrared source, an aperture stop, an infrared integrating sphere, a collimator, and a polarization adjustment module. The polarization adjustment module includes an adjustment cavity and four infrared optical plates. One end of the adjustment cavity is provided with an entrance hole, which is set on the output optical path of the collimator. The other end is provided with an exit hole. The four infrared optical plates are located between the entrance hole and the exit hole, and are divided into two groups along the direction from the entrance hole to the exit hole. The first two infrared optical plates form one group, and the last two infrared optical plates form another group. The two infrared optical plates in each group are arranged in parallel and spaced apart. The two groups of infrared optical plates are symmetrically arranged in the vertical direction, so that the entrance hole and the exit hole are located on the same horizontal line. The radiation light wave output by the collimator passes through the four infrared optical plates in sequence and outputs linearly polarized light with a polarization degree corresponding to the incident angle from the exit hole. Each infrared optical plate is mounted on the middle side of the bracket and connected to the output shaft of the servo motor, and can rotate synchronously with the output shaft to adjust the tilt angle of the infrared optical plate. The inner side of the adjustment cavity is blackened, and a gas filling inlet is provided on the cavity for filling with cooling inert gas to eliminate the influence of its own thermal radiation. This radiation source has higher precision and continuously adjustable infrared polarization, significantly improving the accuracy and dynamic range of the output linear polarization of existing infrared polarization radiation sources. The radiation source is simple in structure, portable, and easy to adjust, enabling continuous adjustment of the output infrared polarization within the range of 0-0.92. This approximately doubles the linear polarization of existing transmission-type infrared polarization radiation sources while maintaining high precision, meeting the testing needs of the aerospace field. Attached Figure Description

[0018] The accompanying drawings are provided for illustrative purposes only, and the proportions and quantities of the components in the drawings may not be consistent with the actual product.

[0019] Figure 1 This is a schematic diagram of the structure of a high-precision controllable medium- and long-wave infrared polarization radiation source in an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the connection between the infrared optical flat panel and the servo motor in an embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of another high-precision controllable medium- and long-wave infrared polarization radiation source in an embodiment of the present invention.

[0022] In the picture:

[0023] 1: Silicon carbide rod infrared source;

[0024] 2: Aperture stop;

[0025] 3: Infrared integrating sphere;

[0026] 4: Parallel light tube;

[0027] 5: Polarization degree adjustment module;

[0028] 51: Adjustment chamber;

[0029] 511: Light entrance aperture;

[0030] 512: Light hole;

[0031] 513: Gas inlet;

[0032] 52: Infrared optical flat panel;

[0033] 53: Bracket;

[0034] 54: Servo motor;

[0035] 541: Output shaft;

[0036] 55: Angle sensor;

[0037] 56: Transillumination. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0040] See Figure 1 and Figure 2 As shown, the high-precision controllable medium- and long-wave infrared polarization radiation source provided in this embodiment of the invention includes a silicon carbide rod infrared source 1, an aperture stop 2, an infrared integrating sphere 3, a collimator 4, and a polarization adjustment module 5. The silicon carbide rod infrared source 1 can emit medium- and long-wave infrared radiation light sources, which are incident into the infrared integrating sphere 3 after passing through the aperture stop 2, and output high-brightness unpolarized radiation light waves. The collimator 4 is set in the output optical path of the infrared integrating sphere 3 to collimate the radiation light waves.

[0041] The polarization adjustment module 5 includes an adjustment cavity 51 and four infrared optical plates 52. One end of the adjustment cavity 51 has an entrance aperture 511, which is located on the output optical path of the collimator 4. The other end has an exit aperture 512. The four infrared optical plates 52 are disposed within the adjustment cavity 51 and between the entrance aperture 511 and the exit aperture 512. The four infrared optical plates 52 are divided into two groups along the direction from the entrance aperture 511 to the exit aperture 512. The first two infrared optical plates 52 form one group, and the last two form another group. The two infrared optical plates 52 in each group are arranged parallel and spaced apart. The two groups of infrared optical plates 52 are... The outer optical plates 52 are symmetrically arranged vertically. The radiated light waves output from the collimator 4 pass through the four infrared optical plates 52 sequentially, undergoing eight refractions, thus producing a polarization effect. Finally, linearly polarized light with a polarization degree corresponding to the incident angle is output from the light exit hole 512. In this embodiment, the design of two sets of infrared optical plates symmetrically arranged vertically ensures that the light path output from the light exit hole 512 is coaxial with the light path input from the light entrance hole 511. Thus, when designing the adjustment cavity 51, it is no longer necessary to calculate and determine the position of the light exit hole 512 through multiple trials. The light exit hole 512 and the light entrance hole 511 are located on the same horizontal line, which facilitates the design of the adjustment cavity. Each infrared optical plate 52 is mounted on a bracket 53. The bracket 53 is connected to the output shaft 541 of the servo motor 54 and can rotate synchronously with the output shaft 541 to adjust the tilt angle of the infrared optical plate 52. The connection between the output shaft 541 and the bracket 53 is located on the side of the bracket 53 and in the middle of the vertical direction. The inner side of the regulating cavity 51 is blackened, and the regulating cavity 51 is also provided with a gas filling inlet 513 for filling with refrigerating inert gas.

[0042] In operation, the silicon carbide rod infrared source 1 emits medium-to-long-wave infrared radiation, which passes through the aperture stop 2 and enters the infrared integrating sphere 3. After multiple diffuse reflections within the infrared integrating sphere 3, it finally outputs high-brightness unpolarized radiation, which is then collimated by the collimator 4. The polarization adjustment module 5 is located on the output optical path of the collimator 4 and includes an adjustment cavity 51 and four infrared optical plates 52. The adjustment cavity 51 has an entrance aperture 511 and an exit aperture 512 at opposite ends. The four infrared optical plates 52 are spaced apart within the adjustment cavity 51 and located between the entrance aperture 511 and the exit aperture 512. The collimated radiation is incident on the entrance aperture 511 of the polarization adjustment module 5. The radiation output from the collimator 4 passes sequentially through the four infrared optical plates 52 and outputs linearly polarized light with a polarization degree corresponding to the incident angle θ1 from the exit aperture 512. During operation, inert gas is introduced through the gas inlet 513 to cool the entire polarization adjustment module 5, eliminating the influence of its own thermal radiation. The inner side of the adjustment cavity 51 is blackened. The infrared optical plate 52 is connected to the output shaft 541 of the servo motor 54 via the bracket 53, with the connection point located in the middle of the side. The tilt angle θ2 of the infrared optical plate is adjusted. During rotational adjustment, the rotation center position of the infrared optical plate remains unchanged, i.e., the position of the infrared optical plate 52 remains unchanged, so that the incident area of ​​the incident light remains basically unchanged, and only the incident angle changes, thus improving accuracy. This invention has higher accuracy and continuously adjustable infrared polarization degree, significantly improving the accuracy and dynamic range of the output linear polarization degree of existing infrared polarization degree radiation sources. This radiation source has a simple structure, is portable, and easy to adjust. It can achieve continuous adjustment of the output infrared polarization degree within the range of 0-0.92, increasing the output linear polarization degree of existing transmission-type infrared polarization degree radiation sources by about one time, and with high accuracy, it can meet the testing needs of the aerospace field.

[0043] To further improve accuracy, see Figure 2 As shown, in some embodiments, the servo motor 54 is located outside the adjustment cavity 51, and one end of the output shaft 541 extends into the adjustment cavity 51 and is connected to the bracket 53.

[0044] In some embodiments, the output shaft 541 is also connected to an angle sensor 55 for real-time measurement of the rotation angle of the infrared optical plate 52. The angle sensor 55 is located outside the adjustment cavity 51, which can further improve the accuracy.

[0045] In this embodiment, the effective light transmission apertures of the light inlet aperture 511 and the light outlet aperture 512 are the same and larger than the effective light transmission aperture of the collimator 4.

[0046] In this embodiment, the tilt angle of the infrared optical plate ranges from 0° to 60°.

[0047] In this embodiment, the incident angle θ1 of the infrared light is the same as the tilt angle θ2 of the infrared optical plate.

[0048] In some embodiments, the spacing between the two infrared optical plates 52 in each group is smaller than the spacing between two groups of infrared optical plates 52. Preferably, the infrared optical plate 52 is a single-crystal silicon wafer that can transmit medium-wave radiation (3-5 μm) and long-wave radiation (8-14 μm).

[0049] For example, in this embodiment, the inert gas used for cooling is liquid nitrogen.

[0050] To improve cooling efficiency and thus further enhance accuracy, in some implementation methods, see [reference needed]. Figure 3 As shown, light inlet 511 and light outlet 512 are respectively provided with transparent plates 56 for passing through radiated light waves, and the two transparent plates 56 respectively seal the light inlet 511 and light outlet 512.

[0051] The parts of this invention not described in detail are current technology or common knowledge.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that not every embodiment contains only one independent technical solution, and in the absence of conflict between solutions, the various technical features mentioned in each embodiment can be combined in any way to form other implementation methods that can be understood by those skilled in the art.

[0053] Furthermore, without departing from the scope of the present invention, modifications to the technical solutions described in the foregoing embodiments, or equivalent substitutions of some of the technical features, shall not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-precision controllable mid-to-long-wave infrared polarization radiation source, characterized in that: The system includes a silicon carbide rod infrared source, an aperture stop, an infrared integrating sphere, a collimator, and a polarization adjustment module. The silicon carbide rod infrared source can emit medium- and long-wave infrared radiation light sources, which are incident into the infrared integrating sphere after passing through the aperture stop, and output high-brightness unpolarized radiation light waves. The collimator is set in the output optical path of the infrared integrating sphere to collimate the radiation light waves. The polarization adjustment module includes an adjustment cavity and four infrared optical plates. One end of the adjustment cavity has an entrance hole, which is located on the output optical path of the collimator. The other end has an exit hole. The four infrared optical plates are located between the entrance hole and the exit hole and are divided into two groups along the direction from the entrance hole to the exit hole. The first two infrared optical plates form one group, and the last two infrared optical plates form another group. The two infrared optical plates in each group are arranged parallel and spaced apart. The two groups of infrared optical plates are symmetrically arranged in the vertical direction. The radiation light wave output by the collimator passes through the four infrared optical plates in sequence and is output from the exit hole as linearly polarized light with a polarization degree corresponding to the incident angle. Each infrared optical plate is mounted on a bracket. The bracket is connected to the output shaft of a servo motor and can rotate synchronously with the output shaft to adjust the tilt angle of the infrared optical plate. The connection between the output shaft and the bracket is located on the side of the bracket and in the middle of the vertical direction. The inner side of the regulating cavity is blackened, and the regulating cavity is also provided with a gas filling inlet for filling with refrigerating inert gas.

2. The high-precision controllable mid-to-long-wave infrared polarization radiation source according to claim 1, characterized in that: The servo motor is located outside the adjustment cavity, and one end of the output shaft extends into the adjustment cavity and is connected to the bracket.

3. The high-precision controllable medium- and long-wave infrared polarization radiation source according to claim 2, characterized in that: The output shaft is also connected to an angle sensor for measuring the rotation angle of the infrared optical plate in real time. The angle sensor is located outside the adjustment cavity.

4. The high-precision controllable medium- and long-wave infrared polarization radiation source according to claim 1, characterized in that: The effective light transmission diameters of the light inlet and light outlet are the same and larger than the effective light transmission diameter of the collimator.

5. The high-precision controllable medium- and long-wave infrared polarization radiation source according to claim 1, characterized in that: The tilt angle of the infrared optical plate ranges from 0° to 60°.

6. The high-precision controllable mid-to-long-wave infrared polarization radiation source according to claim 1, characterized in that: The interval between the two infrared optical plates in each group is smaller than the interval between the two groups of infrared optical plates.

7. The high-precision controllable medium- and long-wave infrared polarization radiation source according to claim 1, characterized in that: The infrared optical flat panel is a single-crystal silicon wafer.

8. The high-precision controllable medium- and long-wave infrared polarization radiation source according to claim 1, characterized in that: The inert gas used for refrigeration is liquid nitrogen.

9. The high-precision controllable mid-to-long-wave infrared polarization radiation source according to claim 1, characterized in that: The light inlet and the light outlet are respectively provided with transparent plates for passing through the radiated light waves, and the two transparent plates respectively seal the light inlet and the light outlet.

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