Backscattering light testing system and method of telescope system

Abstract

The invention relates to a system and a method for testing back scattering light of a telescope system, and mainly solves the technical problem that the existing testing method can only measure stray light outside a field of view and cannot meet the testing requirement of the back scattering light. The test system comprises a laser light source, and a wave plate, a polarization beam splitter, a beam splitter and an information acquisition and processing unit which are sequentially arranged along an emergent light path of the laser light source, the wave plate is a half-wave plate; a first light trap is arranged on a reflection light path of the polarization beam splitter; a second light trap is arranged on a reflection light path of the beam splitter, and a third light trap is arranged at the outlet end of the telescope system; the information collecting and processing unit comprises a camera and a signal processing module, and the camera is located on the other reflection light path of the beam splitter and used for collecting back scattering light and transmitting the back scattering light to the signal processing module; and the signal processing module is used for calculating and processing the received backscattered light and outputting a test result. On the basis, the invention further provides a testing method of the testing system.

Description

Technical Field

[0001] The invention relates to a stray light testing system and method, and in particular to a backscattered light testing system and method for a telescope system. Background Art

[0002] Transceiver-integrated optical systems, such as gravitational wave telescope systems, laser communication telescope systems, laser gyroscopes, etc., the complexity of stray light suppression and evaluation of such systems partly stems from the interaction between incident light and received light. The reason is that in order to ensure that such systems have enough energy for long-distance transmission or high-precision measurement, the incident light is usually a strong laser. However, when this strong laser interacts with optical elements or target surfaces, it will generate backscattered light. Due to its intensity and spectral characteristics, this backscattered light will cause significant interference to the received weak signal light. The interference of backscattered light not only affects the clarity of the signal, but may also introduce additional noise, thereby reducing the signal-to-noise ratio of the optical system. Therefore, the importance of backscattered light testing in transceiver-integrated optical systems is self-evident, especially in application scenarios of high-precision and long-distance transmission.

[0003] In an integrated transceiver optical system, the suppression and testing of backscattered light faces unique challenges because it involves light in the normal optical path, which makes traditional suppression methods such as shielding and spraying matte black paint no longer applicable. Existing stray light test methods are mainly used to test stray light outside the field of view. Since the incident light is in the same optical path as the backscattered light, the backscattered light is blocked during the test and cannot be measured. Therefore, the existing stray light test methods cannot meet the testing needs of backscattered light. Summary of the invention

[0004] The purpose of the present invention is to solve the technical problem that the existing testing method can only measure stray light outside the field of view but cannot meet the backscattered light testing requirements, and to provide a backscattered light testing system and method for a telescope system.

[0005] To achieve the above objectives, the technical solution provided by the present invention is: A backscattered light testing system for a telescope system has the following features: It includes a laser light source, a wave plate, a polarization beam splitter, a beam splitter, and an information acquisition and processing unit which are sequentially arranged along the outgoing light path of the laser light source; The wave plate is a half-wave plate, which is used to rotate the polarization degree of the outgoing light; A first light trap is provided on the reflection light path of the polarization beam splitter, and the outgoing light of the laser light source is divided into two paths after passing through the polarization beam splitter, wherein the S light in the outgoing light is reflected by the polarization beam splitter and absorbed by the first light trap; and the P light in the outgoing light is transmitted through the polarization beam splitter and enters the beam splitter. A second light trap is provided on the reflected light path of the beam splitter, and the P light in the outgoing light is divided into two paths after passing through the beam splitter, one of which is absorbed by the second light trap after being reflected by the beam splitter, and the other is transmitted through the beam splitter into the telescope system; A third light trap is provided at the exit end of the telescope system. After the P light enters the telescope system, a part of it enters the third light trap, and the other part generates backscattered light in the telescope system, and then enters the information collection and processing unit after being reflected by the beam splitter. The information acquisition and processing unit includes a camera and a signal processing module connected to the camera; the camera is located on the back reflection light path of the beam splitter, and is used to collect backscattered light and transmit it to the signal processing module; the camera is connected to the laser light source, and is used to receive the start signal emitted by the laser light source; the signal processing module is used to calculate and process the received backscattered light and output the test results.

[0006] Furthermore, the distance between the center point of the beam splitter and the entrance of the telescope system is Δ1, the distance between the center point of the beam splitter and the second light trap is Δ2, and (Δ1-Δ2)> ; The distance between the third light trap and the telescope system exit is Δ3, and Δ3> ; Where T is the temporal resolution of the camera.

[0007] Furthermore, the laser light source is a picosecond pulse laser, and an optical isolator is provided between the laser light source and the wave plate to improve the transmission efficiency of the output light.

[0008] Furthermore, it also includes a lens arranged between the polarization beam splitter and the beam splitter, which is used to adjust the beam waist aperture of the P light transmitted through the polarization beam splitter.

[0009] Furthermore, a polarizing plate is provided at the entrance end of the camera for adjusting the polarization degree of the light signal.

[0010] At the same time, the present invention also provides a backscattered light testing method for a telescope system, comprising the following steps: Step 1, calibrate the incident light energy of the telescope system to obtain the initial incident light energy P0; Step 2, assembling the backscattered light test system of the telescope system; Step 3, turn on the laser light source to emit outgoing light, and at the same time send a start signal to the camera to put the camera into working state; Step 4, the outgoing light is divided into two paths after passing through the wave plate and the polarization beam splitter in sequence, wherein the S light in the outgoing light is absorbed by the first light trap after reflection; the P light in the outgoing light enters the beam splitter after transmission, and then is divided into two paths again, one of which is absorbed by the second light trap after reflection, and the other enters the telescope system after transmission; Step 5: After the P light enters the telescope system, a part of it enters the third light trap, and the other part generates backscattered light in the telescope system, and then enters the camera after being reflected by the beam splitter; Step 6: The camera transmits the backscattered light to the signal processing module, and the signal processing module obtains the incident light energy P corresponding to the backscattered light. bs ; Step 7: Based on the initial incident light energy P0 obtained in step 1 and the incident light energy P obtained in step 6 bs , the backscattered light suppression capability of the telescope system is calculated, thereby realizing the test of the backscattered light of the telescope system.

[0011] Furthermore, in step 1, the calibration method is specifically as follows: 1.1. Assemble a calibration system according to the backscattered light test system of the telescope system, wherein the camera is moved to the entrance pupil position of the telescope system; the distance between the center point of the beam splitter and the camera entrance pupil plane is Δ4, the distance between the center point of the beam splitter and the second light trap is Δ2, and (Δ4-Δ2)> ;in, c is the speed of light in a vacuum, T is the temporal resolution of the camera; 1.2. Turn on the laser light source, and the emitted light passes through the wave plate, polarization beam splitter, and beam splitter in sequence before being received by the camera; 1.3. The camera transmits the received optical signal of the outgoing light to the signal processing module, which calculates and outputs the energy of the optical signal. The energy P0 is the incident light energy of the telescope system, thus completing the calibration.

[0012] Furthermore, in step 2, during assembly, the distance between the center point of the beam splitter and the entrance of the telescope system is Δ1, and the distance between the center point of the beam splitter and the second light trap is Δ2, and the two must satisfy: (Δ1-Δ2)> , where T is the temporal resolution of the camera, c is the propagation speed of light in vacuum; the distance between the third light trap and the telescope system exit is Δ3, then Δ3 must satisfy Δ3> .

[0013] Furthermore, in step 5, the backscattered light entering the camera also contains interference scattered light, and the interference scattered light includes scattered light from the beam splitter, backscattered light from the second light trap, and backscattered light from the third light trap.

[0014] Furthermore, step 6 is specifically that the camera transmits the backscattered light to the signal processing module, and the signal processing module calculates the time for the backscattered light from the telescope system and the interference scattered light to reach the camera, classifies and outputs the arrival time of each scattered light, and then extracts the scattered light arriving within a preset time period from the output result, thereby obtaining the number of backscattered light photons required for the test, and then calculating the corresponding incident light energy P bs .

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention adopts polarization and beam splitting technology to realize common optical path testing. This method allows the test light (i.e., the outgoing light emitted by the laser light source) and the backscattered light to propagate on the same optical path, effectively solving the problem of the backscattered light being blocked. At the same time, the backscattered light can be collected and accurately selected through the camera and signal processing module, thereby improving the test accuracy of the backscattered light.

[0016] 2. The present invention improves the efficiency and accuracy of the signal in the subsequent processing process by reasonably setting the relative distance between the components, thereby improving the test efficiency and test accuracy of the backscattered light.

[0017] 3. The present invention provides an efficient and accurate testing platform for studying and analyzing the backscattering characteristics of telescope systems. This method is particularly suitable for fields that require precise testing and control of backscattered light characteristics, such as material science, space exploration, and lidar research. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic structural diagram of an embodiment of a backscattered light testing system for a telescope system of the present invention.

[0019] Figure 2 Schematic diagram of the structure of the initial incident light energy calibration system in the embodiment of the backscattered light testing method of the telescope system of the present invention.

[0020] Figure 3 Schematic diagram of the pulsed laser of the laser light source and the light signal received by the camera in the embodiment of the backscattered light testing method of the telescope system of the present invention.

[0021] The following are the descriptions of the reference numerals: 1-laser light source, 2-wave plate, 3-polarization beam splitter, 4-beam splitter, 5-telescope system, 6-first light trap, 7-second light trap, 8-third light trap, 9-camera, 10-signal processing module, 11-optical isolator, 12-lens, 13-polarizer. DETAILED DESCRIPTION

[0022] In order to make the purpose, advantages and features of the present invention clearer, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0023] like Figure 1 As shown, this embodiment provides a backscattered light testing system for a telescope system, including a laser light source 1, a wave plate 2, a polarization beam splitter 3, a beam splitter 4, and an information acquisition and processing unit, which are sequentially arranged along the outgoing light path of the laser light source 1.

[0024] The laser light source 1 is a picosecond pulse laser, which is used to generate test light (i.e., output light) of a specified wavelength. In order to improve the transmission efficiency of the output light, this embodiment also provides an optical isolator 11 at the output end of the laser light source 1 (i.e., between the laser light source 1 and the wave plate 2), so that the output light of the specified wavelength can be transmitted quickly.

[0025] The wave plate 2 is a half-wave plate, i.e., a λ / 2 wave plate, which is used to rotate the polarization degree of the outgoing light. The wave plate 2 is used in conjunction with the polarization beam splitter 3 to form a beam splitter with a variable ratio. The polarization degree of the polarization beam splitter 3 is determined according to the measurement requirements of the telescope system 5. Generally, the higher the polarization degree, the higher the measurement accuracy.

[0026] The polarization beam splitter 3 has a splitting ratio of 50:50, and a first light trap 6 is provided on its reflected light path. The outgoing light of the laser light source 1 is divided into two paths after passing through the polarization beam splitter 3, wherein the S light in the outgoing light is reflected by the polarization beam splitter 3 and absorbed by the first light trap 6; and the P light in the outgoing light is transmitted through the polarization beam splitter 3 and enters the beam splitter 4. In this embodiment, a lens 12 is further provided between the polarization beam splitter 3 and the beam splitter 4, for adjusting the beam waist aperture of the P light transmitted through the polarization beam splitter 3.

[0027] The beam splitter 4 has a splitting ratio of 50:50, and a second light trap 7 is arranged on its reflected light path. The P light transmitted through the polarization beam splitter 3 is divided into two paths after passing through the beam splitter 4, one of which is absorbed by the second light trap 7 after being reflected by the beam splitter 4, and the other is transmitted through the beam splitter 4 into the telescope system 5.

[0028] In this embodiment, the distance between the center point of the beam splitter 4 and the entrance of the telescope system 5 is Δ1, and the distance between the center point of the beam splitter 4 and the second light trap 7 is Δ2, and the two should satisfy: (Δ1-Δ2)> ,in, c is the propagation speed of light in vacuum, and T is the time resolution of camera 9.

[0029] In order to improve the test accuracy, the third light trap 8 is provided at the exit of the telescope system 5 in this embodiment. The distance between the third light trap 8 and the exit of the telescope system 5 is Δ3, and Δ3> After the P light enters the telescope system 5, a part of it enters the third light trap 8, and the other part generates backscattered light in the telescope system 5. The outgoing light scattered light is the signal light required for the test. The backscattered light is reflected by the beam splitter 4 and enters the information collection and processing unit.

[0030] The information collection and processing unit includes a camera 9 and a signal processing module 10 connected to the camera 9; the camera 9 is located on the back reflection light path of the beam splitter 4 (i.e., the light path opposite to the direction of the second light trap 7), and is used to collect backscattered light and transmit it to the signal processing module 10.

[0031] In this embodiment, the camera 9 is an ultrafast camera, which has extremely high time resolution and can usually record transient phenomena of scattered light on a time scale of picoseconds (ps) and femtoseconds (fs). A polarizer 13 is also provided at the entrance of the camera 9, which can adjust the polarization degree of the backscattered light received by the camera 9 according to the polarization characteristics of the scattered light of the telescope system 5. The camera 9 is connected to the laser light source 1, which will also emit a reference signal to the camera 9 while emitting the outgoing light, so that it can start working synchronously.

[0032] The signal processing module 10 is used to perform calculation processing on the received backscattered light and output the result.

[0033] The working principle of the test system of the present invention is: the pulse laser passes through the polarization beam splitter 3, the polarization beam splitter 3 transmits P light and reflects S light, the P light is split by the beam splitter 4 and then incident on the telescope system 5, and the backscattered light generated by the telescope system 5 is reflected by the beam splitter 4 and then received by the camera 9.

[0034] In this process, the P light will generate scattered light (i.e., volume scattering) after passing through the beam splitter 4, the telescope system 5 will generate backscattered light, and the second light trap 7 and the third light trap 8 will also generate corresponding backscattered light. Therefore, the backscattered light received by the camera 9 includes not only the backscattered light of the telescope system 5, but also the scattered light from the beam splitter 4 and the backscattered light generated by the second light trap 7 and the third light trap 8. However, only the backscattered light returned by the telescope system 5 is the signal light that needs to be detected, and the other scattered light is interference scattered light at this time. Since the interference scattered light is useless for the signal light, it is collectively referred to as light pollution.

[0035] The existence of the above light pollution will limit the test accuracy of the test system. Therefore, suppressing the above light pollution is a key technology of the stray light test system. In this embodiment, the camera 9 is used to identify the above different scattered light signals. As mentioned above, the distance between the center point of the beam splitter 4 and the entrance of the telescope system 5 is Δ1, the distance between the center point of the beam splitter 4 and the second light trap 7 is Δ2, and the distance between the third light trap 8 and the exit of the telescope system 5 is Δ3. From the entrance of the telescope system 5 to the exit of the telescope system 5, the longest optical path experienced by the light in the normal optical path is Δ opt The specific positions of the components are set so that different scattered lights arrive at the camera 9 at different times. Finally, the received scattered light is processed by the signal processing module 10, so as to accurately extract the backscattered light information of the telescope system 5.

[0036] This embodiment also provides a backscattered light testing method for a telescope system, comprising the following steps: Step 1: calibrate the incident light energy of the telescope system 5.

[0037] The purpose of calibration is to obtain the initial incident light energy, so as to obtain the reference value required for backscattered light testing. Figure 2 , the calibration method is: According to the backscattered light test system of the telescope system of this embodiment, the components are assembled. During calibration, the telescope system 5 is not required. The camera 9 only needs to be placed at the entrance pupil position of the telescope system 5 and connected to the signal processing module 10. During the assembly process of the components, the distance between the center point of the beam splitter 4 and the entrance pupil plane of the camera 9 is Δ4, and Δ4=Δ1, and the distance between the center point of the beam splitter 4 and the second light trap 7 is Δ2, and (Δ1-Δ2)> .

[0038] After assembly, turn on the laser light source 1, and the emitted light is received by the camera 9 after passing through the optical isolator 11, wave plate 2, polarization beam splitter 3, lens 12, and beam splitter 4 in sequence. At this time, the gain of the camera 9 is set according to the signal strength of the emitted light. And the accumulated number of frames of the received optical signal After the emitted light is stable, the camera 9 transmits the received light signal to the signal processing module 10, which calculates and outputs the number of photons of the light signal. M 0, thus obtaining the initial incident light energy P0, namely:

[0039] The incident light energy P0 is the incident light energy of the calibrated telescope system 5 .

[0040] Step 2: According to Figure 1The structure shown in the figure is used to assemble the backscattered light test system of the telescope system of this embodiment, and the distance between the center point of the beam splitter 4 and the entrance of the telescope system 5 is kept at Δ1, and the distance between the center point of the beam splitter 4 and the second light trap 7 is kept at Δ2, and (Δ1-Δ2)> The distance between the third light trap 8 and the telescope system 5 exit is Δ3, and Δ3> .

[0041] Step 3: The laser light source 1 emits light and sends a start signal to the camera 9 at the same time, thereby realizing synchronous control of the laser light source 1 and the camera 9.

[0042] Step 4, the outgoing light is divided into two paths after passing through the optical isolator 11, the wave plate 2, and the polarization beam splitter 3 in sequence, wherein the S light in the outgoing light is reflected and then absorbed by the first light trap 6, and the P light in the outgoing light is transmitted and then enters the beam splitter 4 through the lens 12. The P light is further divided into two paths by the beam splitter 4, one of which is absorbed by the second light trap 7 after reflection, and the other enters the telescope system 5 after transmission; of the P light after entering the telescope system 5, a part enters the third light trap 8, and the other part generates backscattered light in the telescope system 5, and then enters the camera 9 after being reflected by the beam splitter 4. At this time, the gain of the camera 9 is reset to 1 according to the signal strength of the backscattered light. , and at the same time, the accumulated frame number of the light signal received by camera 9 is set to AC bs The camera 9 transmits the received backscattered light to the signal processing module 10, and the signal processing module 10 outputs the number of photons of the backscattered light.

[0043] Step 5: Since the backscattered light received by the camera 9 also contains interfering scattered light, it includes scattered light from the beam splitter 4, backscattered light from the second light trap 7, and backscattered light from the third light trap 8. Based on this, the time of each scattered light received by the camera 9 can be different according to the interval between the components in step 2, and then each scattered light and the corresponding time information are synchronously transmitted to the signal processing module 10, and the signal processing module 10 can calculate and identify different scattered lights, and then extract the photon number of the backscattered light returned by the telescope system 5. M bs Finally, the incident light energy P entering the telescope system 5 can be obtained by calculation. bs , P bs Calculated by the following formula: .

[0044] Step 6: Based on the incident light energy P0 calibrated in step 1 and the incident light energy P calculated in step 5 bs , and further calculate the backscattered light suppression capability of telescope system 5 S ,Right now: .

[0045] In this embodiment, the signal processing module 10 processes the backscattered light by respectively calculating the time for the backscattered light from the telescope system 5 and the interference scattered light to reach the camera 9, specifically: According to the spacing between the components in the above test system, refer to Figure 3 , the scattered light generated after the outgoing light reaches the beam splitter 4 is first received by the camera 9. Assuming that the time it takes is T1, the time it takes for the backscattered light returned by the second light trap 7 to reach the camera 9 is T2, that is, T2=T1+ The time that the outgoing light passes through the telescope system 5 and the backscattered light returns is between T3 and T4, where T3 = T1 + , T4=T1+ Since the outgoing light enters the telescope system 5 and is usually transmitted along the normal optical path, the outgoing light is incident on the surface of the optical element, generating primary backscattered light, and the contribution of secondary scattered light is too small to be ignored, then the longest optical path of the primary backscattered light is Δ opt It is approximately equal to the longest optical path of the normal optical path in the telescope system 5 from the entrance to the exit of the telescope system 5. In addition, the time experienced by the backscattered light returned by the third optical trap 8 is T5, T5=T1+ .

[0046] In summary, the order in which the camera 9 receives the scattered light is the scattered light generated by the beam splitter 4, the backscattered light generated by the second light trap 7, the backscattered light of the telescope system 5, and the backscattered light generated by the third light trap 8. The camera 9 identifies the above four scattered lights, and then the signal processing module 10 can classify and output them according to the time when each scattered light reaches the camera 9. After that, the scattered light arriving in the corresponding time period can be accurately extracted from the output result, thereby obtaining the backscattered light required for the test.

[0047] The present invention adopts beam splitting technology to realize common optical path testing. This method allows the test light (i.e., the outgoing light emitted by the laser light source) and the backscattered light to propagate on the same optical path, effectively solving the problem of backscattered light being blocked. At the same time, the ultrafast diagnostic technology formed by the ultrafast camera combined with the signal processing module can realize the precise selection of signal light, thereby improving the test accuracy of backscattered light.

[0048] The present invention provides an efficient and accurate testing platform for studying and analyzing backscattering characteristics in optical systems. The method is particularly suitable for fields that require precise testing and control of backscattered light characteristics, such as material science, space exploration, and lidar research.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A backscattered light testing system for a telescope system, characterized in that: It comprises a laser light source (1), a wave plate (2), a polarization beam splitter (3), a beam splitter (4) arranged in sequence along an output light path of the laser light source (1), and an information acquisition and processing unit; The wave plate (2) is a half-wave plate, which is used to rotate the polarization degree of the outgoing light; A first light trap (6) is provided on the reflection light path of the polarization beam splitter (3), and the outgoing light of the laser light source (1) is divided into two paths after passing through the polarization beam splitter (3), wherein S light in the outgoing light is reflected by the polarization beam splitter (3) and absorbed by the first light trap (6); and P light in the outgoing light is transmitted through the polarization beam splitter (3) and enters the beam splitter (4); A second light trap (7) is provided on the reflection light path of the beam splitter (4); light P in the outgoing light is split into two paths after passing through the beam splitter (4); one path is absorbed by the second light trap (7) after being reflected by the beam splitter (4), and the other path is transmitted through the beam splitter (4) and enters the telescope system (5); A third light trap (8) is provided at the exit end of the telescope system (5); after the P light enters the telescope system (5), a portion enters the third light trap (8), and the other portion generates backscattered light in the telescope system (5), which then enters the information collection and processing unit after being reflected by the beam splitter (4); The information acquisition and processing unit comprises a camera (9) and a signal processing module (10) connected to the camera (9); the camera (9) is located on the back reflection light path of the beam splitter (4) and is used to collect backscattered light and transmit it to the signal processing module (10); the camera (9) is connected to the laser light source (1) and is used to receive a start signal emitted by the laser light source (1); the signal processing module (10) is used to perform calculation processing on the received backscattered light and output a test result.

2. The backscattered light testing system of the telescope system according to claim 1, characterized in that: The distance between the center point of the beam splitter (4) and the entrance of the telescope system (5) is Δ1, and the distance between the center point of the beam splitter (4) and the second light trap (7) is Δ2, and (Δ1-Δ2)> ; The distance between the third light trap (8) and the exit of the telescope system (5) is Δ3, and Δ3> ;in, c is the speed of light in vacuum, and T is the time resolution of the camera (9).

3. The backscattered light testing system of the telescope system according to claim 1 or 2, characterized in that: The laser light source (1) is a picosecond pulse laser, and an optical isolator (11) is provided between the laser light source (1) and the wave plate (2) to improve the transmission efficiency of the emitted light.

4. The backscattered light testing system of the telescope system according to claim 3, characterized in that: It also includes a lens (12) arranged between the polarization beam splitter (3) and the beam splitter (4), which is used to adjust the beam waist aperture of the P light transmitted through the polarization beam splitter (3).

5. The backscattered light testing system of the telescope system according to claim 4, characterized in that: The entrance end of the camera (9) is also provided with a polarizing plate (13) for adjusting the polarization degree of the light signal.

6. A method for testing backscattered light of a telescope system, characterized in that: The following steps are involved: Step 1, calibrating the incident light energy of the telescope system (5) to obtain the initial incident light energy P0; Step 2, assembling the backscattered light testing system of the telescope system according to any one of claims 1 to 5; Step 3, turning on the laser light source (1) to emit output light, and at the same time transmitting a start signal to the camera (9), so that the camera (9) is in a working state; Step 4, the outgoing light passes through the wave plate (2) and the polarization beam splitter (3) in sequence and is divided into two paths, wherein the S light in the outgoing light is absorbed by the first light trap (6) after being reflected; the P light in the outgoing light enters the beam splitter (4) after being transmitted, and is then divided into two paths again, wherein one path is absorbed by the second light trap (7) after being reflected, and the other path enters the telescope system (5) after being transmitted; Step 5, after the P light enters the telescope system (5), a portion of it enters the third light trap (8), and the other portion generates backscattered light in the telescope system (5), and then enters the camera (9) after being reflected by the beam splitter (4); Step 6: The camera (9) transmits the backscattered light to the signal processing module (10), and the signal processing module (10) obtains the incident light energy P corresponding to the backscattered light. bs ; Step 7: Based on the initial incident light energy P0 obtained in step 1 and the incident light energy P obtained in step 6 bs , the backscattered light suppression capability of the telescope system (5) is calculated, thereby realizing the test of the backscattered light of the telescope system.

7. The backscattered light testing method of a telescope system according to claim 6, characterized in that: In step 1, the calibration method is specifically as follows: 1.

1. A calibration system for assembling a backscattered light test system for a telescope system according to any one of claims 1 to 5, wherein the camera (9) is moved to the entrance pupil position of the telescope system (5); the distance between the center point of the beam splitter (4) and the entrance pupil plane of the camera (9) is Δ4, and the distance between the center point of the beam splitter (4) and the second light trap (7) is Δ2, and (Δ4-Δ2)> ;in, c is the speed of light in vacuum, T is the time resolution of the camera (9); 1.

2. Turn on the laser light source (1), and the emitted light passes through the wave plate (2), the polarization beam splitter (3), and the beam splitter (4) in sequence and is then received by the camera (9); 1.

3. The camera (9) transmits the received optical signal of the outgoing light to the signal processing module (10), and the signal processing module (10) calculates and outputs the energy of the optical signal. The energy P0 is the incident light energy of the telescope system (5), thereby completing the calibration.

8. The backscattered light testing method of a telescope system according to claim 6, characterized in that: In step 2, during assembly, the distance between the center point of the beam splitter (4) and the entrance of the telescope system (5) is Δ1, and the distance between the center point of the beam splitter (4) and the entrance of the telescope system (5) is Δ2, and the two must satisfy: (Δ1-Δ2)> , where T is the temporal resolution of the camera, c is the propagation speed of light in vacuum; the distance between the third light trap (8) and the exit of the telescope system (5) is Δ3, then Δ3 must satisfy Δ3> .

9. The backscattered light testing method of a telescope system according to claim 8, characterized in that: In step 5, the backscattered light entering the camera (9) also contains interference scattered light, and the interference scattered light includes scattered light from the beam splitter (4), backscattered light from the second light trap (7) and backscattered light from the third light trap (8).

10. The backscattered light testing method of a telescope system according to claim 9, characterized in that: Step 6 specifically includes: the camera (9) transmits the backscattered light to the signal processing module (10), and the signal processing module (10) calculates the time when the backscattered light and the interference scattered light from the telescope system (5) arrive at the camera, classifies and outputs the arrival time of each scattered light, and then extracts the scattered light that arrives within a preset time period from the output result, thereby obtaining the number of photons of the backscattered light required for the test, and then calculating the corresponding incident light energy P bs .

Images