Optical element performance test system and method based on ultralow-temperature high-vacuum coupling

Abstract

The invention relates to an optical element testing system, in particular to an optical element performance testing system and method based on ultralow-temperature high-vacuum coupling, and aims to solve the problem that an existing testing system cannot test the performance of an optical element while simulating an ultralow-temperature and ultrahigh-vacuum sequential coupling environment. Precision testing equipment is protected, and all-parameter and multi-attitude stable and accurate testing of the optical element is achieved. The system comprises a testing container and a tested container which are communicated with each other, and a high-reflectivity one-way film evaporation container is arranged in the testing container and used for slowing down temperature and pressure sudden change during vacuumizing so as to protect internal testing equipment; a contact type optical element clamping cold box is arranged in the tested container, is connected with the optical element through a flexible cold chain, and is matched with a liquid nitrogen / gas nitrogen system to realize proportional temperature regulation. The device can safely and truly simulate the extreme environment of a spaceflight deep space, and achieves the stable and accurate testing of all parameters and multiple attitudes of the optical element.

Description

Technical Field

[0001] This invention relates to an optical component testing system, specifically to an optical component performance testing system and method based on ultra-low temperature high vacuum coupling. Background Technology

[0002] Optical systems, operating in extreme environments such as deep space exploration and cryogenic physics experiments, must withstand the combined effects of ultra-low temperatures and ultra-high vacuum for extended periods. Under this combined stress field, optical components are prone to various performance degradation and even failure phenomena, including: 1) Material property variation: In the coupled environment of ultra-low temperature and high vacuum, key parameters of optical materials such as refractive index and coefficient of thermal expansion will change significantly, and may even cause material embrittlement, affecting its optical performance and structural integrity. 2) Surface condition changes: In a high vacuum environment, gas molecules adsorbed on the surface of optical components are prone to desorption, which leads to changes in their reflectivity or transmittance, thereby affecting the overall performance of the optical system. 3) Thermal stress and structural deformation: Temperature gradients can easily cause stress concentration inside optical components, which may lead to mirror distortion, decreased surface accuracy or cracking of optical coatings, seriously affecting imaging quality and system stability.

[0003] Currently, most common testing equipment and methods can only apply loads to a single physical field (such as only cryogenic or only vacuum), or perform performance evaluations only under normal temperature and pressure conditions. They cannot realistically simulate extreme conditions where ultra-low temperatures and high vacuum coexist and change over time. In addition, existing testing systems often struggle to achieve precise cryogenic control while maintaining high vacuum, or cannot protect precision testing equipment (such as interferometers) from damage in a dual-field coupling environment, resulting in significant deviations between test results and actual on-orbit performance.

[0004] Therefore, there is an urgent need for a system and method that can operate stably in a coupled environment of ultra-low temperature (e.g. -173℃) and ultra-high vacuum (≤10⁻³ Pa) and can perform full-parameter and multi-attitude performance testing on optical components, so as to support the ground verification and failure analysis of key components in fields such as aerospace optical payloads, cryogenic optical instruments and quantum communication devices. Summary of the Invention

[0005] The purpose of this invention is to solve the problem that existing testing systems cannot protect precision testing equipment and achieve stable and accurate testing of all parameters and multiple orientations of optical components while simulating ultra-low temperature and ultra-high vacuum time-coupled environments. Therefore, this invention provides an optical component performance testing system and method based on ultra-low temperature and high vacuum coupling.

[0006] The design concept of this invention is as follows: First, it separates the test sample and the testing equipment using dual vacuum containers, placing them in different stress fields to ensure adaptability. Second, it employs a novel auxiliary fixture to reduce the pumping rate and temperature drop, ensuring the testing equipment is not damaged by the dual stress fields. Finally, it utilizes a novel heat conduction device to ensure the temperature of the optical components is adjustable and controllable within the testing range.

[0007] To achieve the above objectives, the technical solution provided by this invention is: An optical component performance testing system based on ultra-low temperature high vacuum coupling is used to test the performance data of optical components. Its unique feature is that: It includes an internally interconnected test container and a device under test container, a test device placed inside the test container, a pose control module, and a test device control module; the device under test container is used to hold optical components. The test container contains a cylindrical high-reflectivity one-way thin-film evaporation container. A first six-bar linkage is located at the bottom of the high-reflectivity one-way thin-film evaporation container. The test equipment is mounted on the first six-bar linkage, with its probe extending out of one end of the high-reflectivity one-way thin-film evaporation container and facing the placement position of the optical element. Multiple one-way evaporation holes are provided on the wall of the high-reflectivity one-way thin-film evaporation container to slow the gas flow rate and control the airflow direction during vacuuming. A vacuum flange is located at the other end of the high-reflectivity one-way thin-film evaporation container. The container of the device under test is equipped with an electric translation stage, and a contact optical element clamping cold box is set on the electric translation stage. The contact optical element clamping cold box is equipped with a second six-bar mechanism. The contact optical element clamping cold box has an opening facing the probe of the test equipment and is used to place optical elements inside. The contact optical element clamping cold box is connected to the optical elements placed inside it through a flexible cold chain. The test container and the device under test container are respectively connected to a first vacuum system and a second vacuum system for evacuation. The device under test container is also equipped with a liquid nitrogen / gas nitrogen system, which is used to control the temperature of the optical element by adjusting the ratio of gaseous nitrogen to liquid nitrogen introduced into the cold box holding the contact optical element. The test equipment is electrically connected to the test equipment control module, and the first six-bar linkage, the second six-bar linkage, and the electric translation stage are all electrically connected to the posture control module. Both the test equipment control module and the posture control module are electrically connected to an external host computer.

[0008] Furthermore, the testing equipment is supported by the first six-bar linkage, and multiple heat insulation pads are provided at the connection interface between the testing equipment and the first six-bar linkage.

[0009] Furthermore, the testing equipment is a ZYGO interferometer or a 4D dynamic interferometer; the optical element is a single lens, a single mirror, a lens group of multiple lenses and / or mirrors, or a device coated with an optical thin film.

[0010] Furthermore, the test container and the device under test container are connected by a vacuum bellows; the end of the test container away from the vacuum bellows is provided with a test container door, and the end of the device under test container away from the vacuum bellows is provided with a device under test container door.

[0011] Furthermore, a support base is provided at the bottom of the test container, and the high-reflectivity unidirectional thin-film evaporation container is mounted on the support base.

[0012] Furthermore, the inner wall of the high-reflectivity unidirectional thin-film evaporation container is covered with a thin-film layer for further mitigating airflow and isolating heat radiation, and the thin-film layer is made of polytetrafluoroethylene.

[0013] Meanwhile, this invention also provides a method for testing the performance of optical components based on ultra-low temperature high vacuum coupling. The method employs the aforementioned optical component performance testing system based on ultra-low temperature high vacuum coupling, and its unique feature lies in the inclusion of the following steps: Step 1: Open the door of the test container, place the test equipment inside the test container, and connect and fix it to the first six-bar linkage; connect the test equipment to the test equipment control module through the vacuum flange for remote control and data acquisition; then close the door of the test container; open the door of the container under test, install the optical element to be tested in the contact optical element clamping cold box and connect it to the flexible cold chain, connect the optical element to the second six-bar linkage through the clamping fixture, and then close the door of the container under test. Step 2: Start the first vacuum system and the second vacuum system to evacuate the test container and the container of the device under test, so that the internal pressure of both reaches their respective preset vacuum levels; during this process, the rate of decrease in gas pressure and temperature inside the test container is slowed down by the high reflectivity unidirectional thin film evaporation container. Step 3: After the vacuum levels of both the test container and the container of the device under test reach their respective preset vacuum levels, start the liquid nitrogen / gas nitrogen system. By adjusting the ratio of gaseous nitrogen to liquid nitrogen introduced into the cold box holding the contact optical element, the optical element is cooled down until its temperature reaches the preset ultra-low temperature test value. Step 4: Start the test equipment and adjust the first six-bar linkage, the second six-bar linkage and / or the electric translation stage through the pose control module to change the relative pose between the test equipment probe and the optical element; under at least one relative pose, use the test equipment to test the optical performance of the optical element and record the test data. Step 5: After the test is completed, heated nitrogen gas is introduced into the cold box holding the contact optical element through the liquid nitrogen / gas nitrogen system to restore the optical element to room temperature; then, nitrogen gas is introduced into the test container and the container of the device under test for repressurization until it is restored to normal pressure, thus completing the test.

[0014] Furthermore, in step 4, the optical performance test is a surface shape test, and the recorded test data includes at least one of the following: PV (Peak-to-Valley) value, RMS (Root Mean Square) value, Power (sphericity or defocus) value, and Zernike coefficient (Zernike polynomial coefficient).

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. The optical component performance testing system based on ultra-low temperature and high vacuum coupling provided by this invention achieves stress field separation between the testing equipment and the optical component under extreme environments through a dual-cavity design that physically isolates the testing container and the tested container. This design allows the precision testing equipment to be placed in a controlled, slowly changing environment for observation, while the tested component bears the full amount of ultra-low temperature and high vacuum coupling stress. This enables the performance testing of optical components under real combined extreme working conditions in engineering, and solves the technical bottleneck that existing equipment cannot simulate the time-series coupling effect.

[0016] 2. The optical component performance testing system based on ultra-low temperature high vacuum coupling provided by this invention integrates a high-reflectivity unidirectional thin film evaporation container with a high-reflectivity inner wall, a polytetrafluoroethylene thin film layer, and controllable unidirectional evaporation orifices, forming a multi-layer protection mechanism for the testing equipment. This design can actively slow down the gas flow rate and temperature drop rate when the system is evacuated, effectively isolating external thermal radiation and thermal stress impact, ensuring the safety and long-term stability of expensive and environmentally sensitive standard testing equipment in harsh testing environments, and overcoming the problem that the testing equipment itself cannot withstand composite stress and is damaged.

[0017] 3. The optical component performance testing system based on ultra-low temperature high vacuum coupling provided by this invention adopts an active temperature control scheme that combines proportional adjustment of a liquid nitrogen / gas nitrogen system with flexible cold chain conduction. This system can achieve rapid, stable, and uniform cooling control of the contact optical component clamping cold box and the component under test by precisely adjusting the gas-liquid two-phase flow ratio, and can maintain high thermal stability at the target ultra-low temperature point. This technology ensures the accuracy and repeatability of temperature conditions during testing, providing a reliable environmental basis for evaluating the low-temperature characteristics, thermal deformation, and thermal stress effects of materials.

[0018] 4. The optical component performance testing system based on ultra-low temperature high vacuum coupling provided by this invention integrates a multi-degree-of-freedom, high-precision collaborative adjustment system consisting of a first six-bar linkage, a second six-bar linkage, an electric translation stage, and a posture control module. This design allows for remote and automatic adjustment of the attitude of the optical component under test relative to the test beam while maintaining the extreme environment unchanged. This supports comprehensive measurement of the performance of the optical component under different assembly states or incident angles, greatly expanding the information dimension and evaluation depth of a single test.

[0019] 5. The optical component performance testing method based on ultra-low temperature high vacuum coupling provided by this invention defines a complete and standardized process from sample loading, composite environment simulation, multi-attitude testing to safe recovery. This method not only ensures the operability and safety of the test, but more importantly, it faithfully reproduces the timing of environmental loads encountered by the spacecraft in orbit through step-by-step control, enabling ground test results to more accurately predict the in-orbit behavior and failure modes of optical components.

[0020] 6. The optical component performance testing method based on ultra-low temperature high vacuum coupling provided by this invention clearly specifies a protective operation in the key vacuuming step: slowing down the rate of decrease in internal gas pressure and temperature of the test container by using a high-reflectivity unidirectional thin-film evaporation container. This method step is the key to transforming the core innovation of the system into an executable process. It quantifies the implementation of the protection process, effectively avoids condensation or thermal shock failures of the test equipment, and significantly extends the service life and measurement accuracy of the equipment in extreme environment testing.

[0021] 7. The optical component performance testing method based on ultra-low temperature high-vacuum coupling provided by this invention achieves precise cooling by adjusting the ratio of gaseous nitrogen to liquid nitrogen introduced into the cold box holding the contact optical component. This method provides a linear and controllable temperature control means, which can more accurately reach and maintain any intermediate low temperature point, reduce temperature overshoot and fluctuations, and provide the possibility for studying the performance inflection point or phase transition behavior of optical components at specific low temperatures.

[0022] 8. The optical component performance testing method based on ultra-low temperature high vacuum coupling provided by this invention proposes to perform measurements in at least one relative pose within a single testing process, and supports expansion to multi-pose automated testing. This method framework ensures basic testing efficiency while providing a standardized procedure for comprehensively evaluating the environmental adaptability of optical components under possible assembly errors or different field of view angles. Combined with automated data recording, this method can systematically generate a multi-dimensional performance dataset, greatly improving the engineering utility and research value of the test. Attached Figure Description

[0023] Figure 1This is a schematic diagram of an embodiment of the optical component performance testing system based on ultra-low temperature high vacuum coupling of the present invention; Figure 2 This is a schematic diagram of the structure of a high-reflectivity unidirectional thin-film evaporation container in an embodiment of the optical component performance testing system based on ultra-low temperature high vacuum coupling of the present invention; The attached figures are labeled as follows: 1-Test container, 101-Test container door, 11-Position control module, 12-Test equipment control module, 13-First vacuum system, 14-High reflectivity unidirectional thin film evaporation container, 1401-Unidirectional evaporation orifice, 15-First six-bar linkage, 16-Test equipment, 1601-Test equipment probe, 17-Insulation pad, 18-Vacuum flange, 19-Support base; 2-Test device container, 201-Test container door, 21-Liquid nitrogen / gas nitrogen system, 22-Contact optical element clamping cold box, 23-Second vacuum system, 24-Electric translation stage, 25-Second six-bar linkage, 26-Flexible cold chain; 3-Vacuum bellows; 4-Optical element. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0025] A performance testing system for optical components based on ultra-low temperature high-vacuum coupling is used to test the performance data of optical component 4 under simulated deep space extreme environments. See also... Figure 1 and Figure 2 It includes a test container 1 and a device under test container 2 that are internally interconnected, and a test device 16 placed inside the test container 1. The device under test container 2 is used to place optical components 4. The test container 1 is equipped with a cylindrical high-reflectivity one-way thin film evaporation container 14. The inner wall of the high-reflectivity one-way thin film evaporation container 14 is covered with a thin film layer for further slowing down airflow and isolating heat radiation. The thin film layer is made of polytetrafluoroethylene.

[0026] A first six-bar linkage 15 is disposed at the bottom of the high-reflectivity unidirectional thin-film evaporation container 14. A testing device 16 is mounted on the first six-bar linkage 15 and supported by it. Multiple heat-insulating pads 17 are provided at the connection interface between the testing device 16 and the first six-bar linkage 15. In this embodiment, the testing device 16 is a ZYGO interferometer. The first six-bar linkage 15 allows for six-degree-of-freedom fine-tuning of the testing device probe 1601 for initial optical path alignment.

[0027] The test probe 1601 of the test device 16 extends from one end of the high-reflectivity one-way thin-film evaporation container 14 and faces the placement position of the optical element 4. The wall of the high-reflectivity one-way thin-film evaporation container 14 is provided with multiple one-way evaporation holes 1401 for slowing down the gas flow rate and controlling the airflow direction during vacuuming. A one-way differential pressure valve is provided at each hole, allowing only gas to flow from the inside of the evaporation container 14 to the external test container 1 cavity. Its core function is dual protection: firstly, the high-reflectivity inner wall effectively reflects thermal radiation, reducing the thermal shock of the external thermal environment to the internal test device 16; secondly, the polytetrafluoroethylene film layer and the one-way holes 1401 work together to greatly slow down the gas outflow rate during system vacuuming, preventing a sudden drop in gas pressure and temperature within the test container 1 cavity, thereby protecting the precision test device 16 (in this embodiment, a ZYGO interferometer), which is extremely sensitive to temperature and pressure changes, from damage. A vacuum flange 18 is provided at the other end of the high-reflectivity one-way thin-film evaporation container 14. The container 2 of the device under test is equipped with an electric translation stage 24. The electric translation stage 24 is equipped with a contact optical element clamping cold box 22. The contact optical element clamping cold box 22 is equipped with a second six-bar mechanism 25. The contact optical element clamping cold box 22 has an opening facing the probe 1601 of the test device. It is used to place the optical element 4. The contact optical element clamping cold box 22 is connected to the optical element 4 placed inside it through a flexible cold chain 26.

[0028] Test container 1 and device under test (DUT) container 2 are respectively connected to a first vacuum system 13 and a second vacuum system 23 for evacuation. DUT container 2 is also equipped with a liquid nitrogen / gas nitrogen system 21, used to control the temperature of optical element 4 by adjusting the ratio of gaseous nitrogen to liquid nitrogen introduced into the cold chamber 22 holding the contact optical element. The key to the liquid nitrogen / gas nitrogen system 21 is its ratio adjustment function: by precisely controlling the mixing ratio of liquid nitrogen and gaseous nitrogen introduced into the cold chamber, the optical element 4 can be cooled linearly and stably and maintained at the required ultra-low temperature test point (e.g., -173℃ or 100K), while avoiding drastic temperature fluctuations. The first vacuum system 13 is responsible for evacuating test container 1 and its internal evaporation container 14, while the second vacuum system 23 is responsible for evacuating DUT container 2. Both can evacuate their respective chambers to a vacuum level of ≤10⁻³Pa to meet ultra-high vacuum test conditions. The two systems can be started, stopped, and monitored independently, ensuring the flexibility of the test.

[0029] The test equipment 16 is electrically connected to the test equipment control module 12. The first six-bar linkage 15, the second six-bar linkage 25, and the electric translation stage 24 are all electrically connected to the posture control module 11. Both the test equipment control module 12 and the posture control module 11 are electrically connected to an external host computer. The second six-bar linkage 25 is responsible for adjusting the pitch, yaw, and rotation attitude of the optical element 4, while the electric translation stage 24 can drive the entire assembly to perform one-dimensional translation. The first six-bar linkage 15, the second six-bar linkage 25, and the electric translation stage 24 are all driven by the posture control module 11, which is linked to the host computer and is programmable, thus enabling precise and automatic adjustment of the optical element 4 to a series of preset test attitudes.

[0030] The test container 1 and the device under test container 2 are connected by a vacuum bellows 3; a test container door 101 is provided at the end of the test container 1 away from the vacuum bellows 3, and a device under test container door 201 is provided at the end of the device under test container 2 away from the vacuum bellows 3. A support base 19 is provided at the bottom inside the test container 1, and a high-reflectivity unidirectional thin film evaporation container 14 is placed on the support base 19.

[0031] In summary, this system, through its physically isolated dual-container design, evaporation container with active protection, precise cryogenic control system based on proportional adjustment, and multi-degree-of-freedom collaborative pose adjustment mechanism, together constructs a safe, reliable, and comprehensive performance testing platform for optical components that can simulate extreme environments of ultra-low temperature and ultra-high vacuum coupling.

[0032] This embodiment also provides a method for testing the performance of optical components based on ultra-low temperature high vacuum coupling, using the aforementioned optical component performance testing system based on ultra-low temperature high vacuum coupling. The following uses the testing of a SiC primary reflector as an example to illustrate the specific implementation process of this method. The test requires simulating the extreme environment the reflector would encounter in actual use: high vacuum (1.3 × 10⁻³ Pa) and ultra-low temperature (100 K), and testing its surface accuracy under different orientations (0″ pose, ±20″ pitch angle, ±20″ azimuth angle) under this environment. The method includes the following steps: Step 1: First, process the test equipment 16 (ZYGO interferometer in this example): connect it to the test equipment control module 12 via vacuum flange 18 for remote control and data acquisition; attach a thermocouple to its surface for real-time temperature monitoring; then, fix it to the first six-bar linkage 15 with screws, and apply anti-loosening adhesive to the screw connection to ensure its stable posture during subsequent testing; process the optical element 4 under test (SiC mirror in this example): attach a thermocouple temperature sensor to its back for accurate temperature monitoring; reliably connect it to the flexible cold chain 26 (copper cold chain can be used in this example); after completing the above processing, open the door 201 of the container under test 2, place the SiC mirror into the contact optical element clamping cold box 22, and connect it to the second six-bar linkage 25 through a special clamping fixture; after confirming that the connection is secure, close the door 201 of the container under test.

[0033] Step 2: After closing all container doors, simultaneously activate the first vacuum system 13 and the second vacuum system 23 to evacuate both the test container 1 and the container under test 2. The goal of evacuation is to ensure that the pressure inside both containers is greater than 1.3 × 10⁻³ Pa. The key to this process is the protection of the internal environment of the test container 1 achieved through the high-reflectivity unidirectional thin-film evaporation container 14. The unidirectional evaporation holes 1401 on the wall of the evaporation container 14 and the polytetrafluoroethylene (PTFE) film layer on its inner wall effectively slow down the gas outflow rate, thereby preventing a sharp drop in internal pressure and temperature of the test container 1 and preventing damage to the precision testing equipment 16 due to thermal stress and sudden pressure changes. Real-time monitoring of the pressure drop inside the evaporation container and the temperature drop on the surface of the testing equipment is necessary to ensure a stable process.

[0034] Step 3: Once the vacuum levels of both containers have stabilized at the preset value (i.e., better than 1.3 × 10⁻³ Pa), an ultra-low temperature environment is created for the optical element 4. The liquid nitrogen / gastric nitrogen system 21 is activated, and a cryogenic medium is injected into the cold box 22 by adjusting the mixing ratio of gaseous and liquid nitrogen supplied to the contact optical element clamping cold box. The cryogenic medium rapidly raises the temperature of the cold box body to the equilibrium point (100K) through thermal conduction. The cold box then continuously and stably transfers the cooling energy to the SiC reflector through the connected flexible cold chain 26 until the thermocouple on the back of the reflector indicates that its temperature has reached and stabilized at the target test temperature of 100K. Step 4: After the SiC mirror temperature stabilizes, power on and start the test equipment 16. Test begins: First, a surface shape test is performed at the "0" reference pose. The first six-bar linkage 15 and / or the second six-bar linkage 25 are adjusted by the pose control module 11 to make the optical axis of the test device probe 1601 precisely coincide with the optical axis of the SiC reflector. Surface shape data is collected and recorded in this state.

[0035] Then, multi-angle tests were conducted. The electric translation stage 24 and the second six-bar linkage 25 were controlled by the pose control module 11 to sequentially adjust the SiC reflector to preset attitudes such as pitch +20″, pitch -20″, azimuth +20″, and azimuth -20″. In each attitude, the surface shape was tested using the testing equipment 16, and the corresponding surface shape error data were recorded, including but not limited to PV value, RMS value, power value, and Zernike coefficient, to comprehensively evaluate the surface shape stability of the reflector in extreme environments.

[0036] Step 5: After all tests are completed, begin the environment recovery process. First, a rewarming process is performed. Heated nitrogen gas (or other nitrogen gas) at about 50°C is introduced into the contact optical element clamping cold box 22 through the liquid nitrogen / gas nitrogen system 21. Heat conduction is carried out in the reverse direction, so that the SiC mirror is heated evenly and slowly until it returns to room temperature.

[0037] Then, a repressurization process is performed. Before repressurization, the power supply to the test equipment 16 is turned off, and the electric translation stage 24 and all six-bar linkages are restored to their initial "0" positions via the posture control module 11. Then, dry nitrogen (or other nitrogen gas) is slowly and controllably introduced into the test container 1 and the container under test 2 until the internal pressure of the two containers returns to normal.

[0038] Finally, the container door was opened, and the test equipment 16 and the SiC mirror under test were taken out in sequence to complete the entire test process. The series of surface shape data obtained through this method can effectively evaluate the performance adaptability and reliability of this optical element under extreme environments of ultra-low temperature and high vacuum coupling.

Claims

1. A performance testing system for optical components based on ultra-low temperature high vacuum coupling, used to test the performance data of optical components (4), characterized in that: It includes a test container (1) and a device under test container (2) that are internally interconnected, a test device (16) placed inside the test container (1), a pose control module (11) and a test device control module (12); the device under test container (2) is used to place optical components (4); The test container (1) is equipped with a cylindrical high-reflectivity one-way thin film evaporation container (14). A first six-bar linkage (15) is provided at the bottom of the high-reflectivity one-way thin film evaporation container (14). The test device (16) is mounted on the first six-bar linkage (15). The test device probe (1601) of the test device (16) extends out of one end of the high-reflectivity one-way thin film evaporation container (14) and faces the placement position of the optical element (4). The wall of the high-reflectivity one-way thin film evaporation container (14) is provided with multiple one-way evaporation holes (1401) for slowing down the gas flow rate and controlling the airflow direction during the vacuuming process. A vacuum flange (18) is provided at the other end of the high-reflectivity one-way thin film evaporation container (14). The test equipment container (2) is equipped with an electric translation stage (24), and a contact optical element clamping cold box (22) is provided on the electric translation stage (24). The contact optical element clamping cold box (22) is equipped with a second six-bar mechanism (25). The contact optical element clamping cold box (22) has an opening facing the test equipment probe (1601) and is used to place optical elements (4). The contact optical element clamping cold box (22) is connected to the optical elements (4) placed inside it through a flexible cold chain (26). The test container (1) and the device under test container (2) are respectively connected to a first vacuum system (13) and a second vacuum system (23) for evacuation. The device under test container (2) is also equipped with a liquid nitrogen / gas nitrogen system (21) for controlling the temperature of the optical element (4) by adjusting the ratio of gaseous nitrogen to liquid nitrogen introduced into the contact optical element clamping cold box (22). The test device (16) is electrically connected to the test device control module (12). The first six-bar linkage (15), the second six-bar linkage (25) and the electric translation stage (24) are all electrically connected to the posture control module (11). The test device control module (12) and the posture control module (11) are both electrically connected to the external host computer.

2. The optical component performance testing system based on ultra-low temperature high vacuum coupling according to claim 1, characterized in that: Multiple heat insulation pads (17) are provided at the connection interface between the test device (16) and the first six-bar linkage (15).

3. The optical component performance testing system based on ultra-low temperature high vacuum coupling according to claim 1, characterized in that: The test device (16) is a ZYGO interferometer or a 4D dynamic interferometer; the optical element (4) is a single lens, a single mirror, a lens group of multiple lenses and / or mirrors, or a device coated with an optical thin film.

4. The optical component performance testing system based on ultra-low temperature high vacuum coupling according to claim 3, characterized in that: The test container (1) and the device under test container (2) are connected by a vacuum bellows (3); a test container door (101) is provided at the end of the test container (1) away from the vacuum bellows (3), and a device under test container door (201) is provided at the end of the device under test container (2) away from the vacuum bellows (3).

5. The optical component performance testing system based on ultra-low temperature high vacuum coupling according to claim 4, characterized in that: The bottom of the test container (1) is provided with a support base (19), and the high reflectivity one-way thin film evaporation container (14) is placed on the support base (19).

6. The optical component performance testing system based on ultra-low temperature high vacuum coupling according to claim 5, characterized in that: The inner wall of the high-reflectivity unidirectional thin-film evaporator (14) is covered with a thin film layer for further slowing down airflow and isolating heat radiation. The thin film layer is made of polytetrafluoroethylene.

7. A method for testing the performance of optical components based on ultra-low temperature high vacuum coupling, employing the optical component performance testing system based on ultra-low temperature high vacuum coupling as described in any one of claims 1 to 6, characterized in that, Includes the following steps: Step 1: Open the test container door (101) of the test container (1), place the test equipment (16) inside the test container (1), and connect and fix it to the first six-bar linkage (15); connect the test equipment (16) to the test equipment control module (12) through the vacuum flange (18) for remote control and data acquisition; then close the test container door (101); open the test container door (201) of the test container (2), install the optical element (4) to be tested in the contact optical element clamping cold box (22) and connect it to the flexible cold chain (26), connect the optical element (4) to the second six-bar linkage (25) through the clamping fixture, and then close the test container door (201); Step 2: Start the first vacuum system (13) and the second vacuum system (23) to evacuate the test container (1) and the test device container (2) so that the internal pressure of both reaches their respective preset vacuum levels; during this process, the high reflectivity one-way thin film evaporation container (14) slows down the rate of decrease of the internal air pressure and temperature of the test container (1); Step 3: After the vacuum levels of the test container (1) and the test equipment container (2) have reached their respective preset vacuum levels, start the liquid nitrogen / gas nitrogen system (21). By adjusting the ratio of gaseous nitrogen to liquid nitrogen introduced into the contact optical element clamping cold box (22), the optical element (4) is cooled down until its temperature value reaches the preset ultra-low temperature test value. Step 4: Start the control test equipment (16), and adjust the first six-bar linkage (15), the second six-bar linkage (25) and / or the electric translation stage (24) through the pose control module (11) to change the relative pose between the test equipment probe (1601) and the optical element (4); under at least one relative pose, use the test equipment (16) to perform optical performance tests on the optical element (4) and record the test data; Step 5: After the test is completed, heated nitrogen gas is introduced into the contact optical element clamping cold box (22) through the liquid nitrogen / gas nitrogen system (21) to restore the optical element (4) to room temperature; Subsequently, nitrogen gas is introduced into the test container (1) and the test device container (2) to repressurize until it is restored to normal pressure, thus completing the test.

8. The optical component performance testing method based on ultra-low temperature high vacuum coupling according to claim 7, characterized in that: In step 4, the optical performance test is a surface shape test, and the recorded test data includes at least one of the following: PV value, RMS value, Power value, and Zernike coefficient of surface shape error.

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