An optical element damage threshold detection system

Abstract

The present application relates to the technical field of optical element detection, and discloses an optical element damage threshold detection system, which comprises a first light source, a switching device, a sample stage, an imaging device and a main controller. The main controller is used to control the switching device to switch the focused optical assembly on any optical mounting position to be located on the main light path of a test light beam. The focused optical assembly on different optical mounting positions comprises a single-lens focusing assembly and a beam-reducing mirror focusing assembly. The light beam shaped by the focused optical assembly is output to a specific point of the measured optical element for damage testing. The damage threshold detection result can be obtained by analyzing the detection images before and after the action of the test light beam using the imaging device. The optical element damage threshold detection system can adapt to the testing requirements of thin film and long crystal optical elements, thereby suppressing the self-focusing of the long crystal and improving the accuracy of the test result.

Description

Technical Field

[0001] This invention relates to the field of optical component testing technology, and more specifically to an optical component damage threshold detection system. Background Technology

[0002] The laser damage threshold of optical components is an important parameter for measuring the ability of materials to withstand high-energy-density laser irradiation.

[0003] Existing laser damage threshold testing platforms generally employ standardized focusing optical path designs. They use a combination of optical components such as a single-focusing mirror and collimator to control the spot size and energy density, adapting to the testing needs of different material systems and damage mechanisms. For damage threshold testing of conventional thin-film optical elements, this traditional optical path configuration can generally meet the testing requirements. However, when testing long-crystal or large-size optical materials, the long optical path length and high nonlinear coefficient of the material itself can easily lead to a significant self-focusing effect under high-energy-density laser irradiation. This effect causes distortion of the equivalent refractive index distribution within the crystal, resulting in laser transmission path deviation, which in turn causes problems such as spot shrinkage, unstable intensity distribution, and even focal point drift, severely interfering with the accuracy of damage threshold testing. Summary of the Invention

[0004] This invention provides an optical element damage threshold detection system to solve the technical problem of inaccurate damage threshold detection results.

[0005] This invention provides an optical element damage threshold detection system, comprising: The first light source is used to output the test beam; The switching device includes a rotating device and a driving device. The rotating device is provided with multiple optical mounting positions for mounting different types of focusing optical components at intervals along the circumferential direction. The focusing optical components include single-lens focusing components and beam-shrinking focusing components. The driving device is used to drive the rotating device to rotate based on received control commands, so that any focusing optical component is located on the main optical path of the test beam. The sample stage is used to set up the optical element under test and position it on the main optical path after the focusing optical assembly. An imaging device used to acquire detection images of the optical element under test before and after the test beam acts on it; The main controller is connected to both the imaging device and the driving device. It is used to send corresponding control commands to the driving device according to the focusing optical components required for the current test, receive the detection images sent by the imaging device, and obtain the damage threshold detection results based on the analysis of the detection images.

[0006] In some embodiments, the drive device includes a drive controller, a drive unit, and a connecting part. The drive controller is connected to the main controller, and the output end of the drive unit is connected to the middle part of the rotating device through the connecting part.

[0007] In some embodiments, the drive device further includes a support, on which the drive unit is mounted.

[0008] In some embodiments, the rotating device employs a rotating sleeve, the center of which is connected to the output end of the drive unit via a connecting part. Optical mounting positions are set on the rotating sleeve, and the distance from the center of the rotating sleeve to the center point of any optical mounting position is equal to the distance from the center of the rotating sleeve to the main optical path.

[0009] In some implementations, the optical element damage threshold detection system further includes an optical path transmission module, which is disposed between the first light source and the switching device, and is used to adjust the propagation direction of the test beam so that the test beam propagates along the main optical path.

[0010] In some embodiments, the test beam output by the first light source has multiple wavelengths. The optical path transmission module includes a first reflector, a second reflector, and a third reflector. The first reflector is used to reflect test beams of several wavelengths to the third reflector. The second reflector is used to reflect test beams of other wavelengths to the third reflector. The third reflector is used to reflect the received test beam and propagate it along the main optical path. The reflection wavelengths of the first reflector and the second reflector are different. The reflection wavelengths of the third reflector include the reflection wavelengths of the first reflector and the second reflector.

[0011] In some embodiments, the optical element damage threshold detection system further includes a second light source and a first beam splitter. The second light source is connected to the main controller, and the first beam splitter is disposed on the main optical path and located between the focusing optical component and the optical element under test. The second light source is used to output a detection beam to the first beam splitter, and the first beam splitter is used to reflect the detection beam to the optical element under test and propagate along the main optical path.

[0012] In some implementations, the optical element damage threshold detection system further includes an optical attenuator disposed on the main optical path and located between the focusing optical component and the first beam splitter.

[0013] In some embodiments, the optical element damage threshold detection system further includes a fourth reflector, which is disposed between the optical element under test and the imaging device, and is used to reflect the scattered light generated after the detection beam passes through the optical element under test to the imaging device, and the imaging device generates a detection image based on the scattered light.

[0014] In some implementations, the sample stage is an electrically controlled displacement stage, which is connected to the main controller and is used to drive the optical element under test to move in at least one direction.

[0015] The present invention has the following beneficial effects: The optical element damage threshold detection system of the present invention uses a main controller to control a switching device to switch the focusing optical component at any optical mounting position to be located on the main optical path of the test beam. The focusing optical components at different optical mounting positions include single-lens focusing components and beam-shrinking focusing components. The single-lens focusing component is suitable for multi-wavelength damage threshold testing of thin-film optical elements, and the beam-shrinking focusing component is used to shrink laser beams of different wavelengths. The main controller can select the focusing optical component required for the current test according to the wavelength of the test beam and the type of the optical element under test, and switch it to the main optical path. The beam shaped by the focusing optical component is output to a specific point of the optical element under test for damage testing. The damage threshold detection result can be obtained by using an imaging device to acquire detection images before and after the test beam is applied. Thus, without changing the first light source and the mounting state of the optical element under test, the focusing mode switching for different types of optical elements under test can be realized, enabling the optical element damage threshold detection system to adapt to the testing requirements of thin-film and long-crystal optical elements, thereby suppressing long-crystal self-focusing and improving the accuracy of test results. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the optical element damage threshold detection system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the switching device according to an embodiment of the present invention.

[0018] Explanation of reference numerals in the attached figures: 1. First light source; 2. First reflector; 3. Second reflector; 4. Third reflector; 5. Drive unit; 6. Rotation device; 7. Connecting part; 8. Support part; 9. Drive controller; 10. Optical attenuator; 11. First beam splitter; 12. Second light source; 13. Sample stage; 14. Optical element under test; 15. Fourth reflector; 16. Imaging device; 17. Main controller. Detailed Implementation

[0019] 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.

[0020] It should be noted that the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection of two components. The terms "parallel," "perpendicular," and "equal" include the described situation and situations that are similar to the described situation, where the range of similarity is within an acceptable deviation range, which is determined by a person skilled in the art taking into account the measurement under discussion and the error associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, "parallel" includes absolute parallelism and approximate parallelism, where the acceptable deviation range for approximate parallelism can be, for example, within 5°; "perpendicular" includes absolute perpendicularity and approximate perpendicularity, where the acceptable deviation range for approximate perpendicularity can also be, for example, within 5°; "equal" includes absolute equality and approximate equality, where the acceptable deviation range for approximate equality can be, for example, the difference between the two equals being less than or equal to 5% of either one. For a person skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0021] The damage threshold of an optical element is the critical value of beam energy / power density at which irreversible optical damage occurs when an optical element is subjected to a specific test beam. It is a core indicator for measuring the laser damage resistance of an optical element. Currently, when testing optical elements, traditional methods rely heavily on frequent manual lens replacements, optical path adjustments, or reselection of the beam ratio to suppress the adverse effects of self-focusing. However, these manual operations are not only inefficient but also easily influenced by the operator's experience, making it difficult to reproduce the optical path state after each adjustment. Furthermore, manual adjustment of optical elements under high-energy laser conditions poses potential dangers, and rapid response of the optical path during adjustment is difficult to achieve, failing to meet the experimental requirements for dynamically switching spot sizes or real-time suppression of self-focusing effects. In addition, traditional optical path structures are mostly fixed configurations, unable to achieve high-precision, low-deviation switching between different focusing methods, thus limiting the applicability of the testing system to different crystal lengths, damage mechanisms, and laser parameters.

[0022] On the other hand, with the diversification of laser applications, more and more damage testing platforms need to support laser testing at different wavelengths, such as 1064 nm, 532 nm, 355 nm, 266 nm, and even other near-infrared and deep ultraviolet bands. Different wavelengths of laser light have different refractive index distributions, focusing characteristics, and nonlinear responses, resulting in significant differences in the optimal focusing position, lens focal length, and beam reduction ratio under multi-wavelength conditions. Furthermore, the absorptivity, group velocity dispersion, and nonlinear optical response of crystal materials differ at different wavelengths, causing the self-focusing threshold to vary with wavelength. Traditional fixed optical configurations struggle to meet the needs of multi-wavelength testing, and cannot achieve rapid switching and optical compensation between different wavelengths, leading to low testing efficiency and poor system adaptability.

[0023] Most existing automated designs only achieve simple optical component movement, lacking specialized optical path planning and dynamic compensation functions for multi-wavelength testing and self-focusing suppression. Therefore, they cannot meet the comprehensive performance requirements of long crystal damage threshold detection, such as rapid lens changing, precise positioning, multi-wavelength adaptation, and self-focusing control.

[0024] To address the above problems, this invention proposes an optical element damage threshold detection system. This system uses a switching device to achieve automated, high-precision, and repeatable rapid switching between different optical elements, such as single-lens focusing components and beam-shrinking focusing components. This allows for the automatic selection of the optimal optical path structure based on different crystal lengths, wavelengths, and testing requirements, thereby suppressing self-focusing and beam distortion caused by long crystals at high energy densities and improving the stability, repeatability, and accuracy of damage threshold testing.

[0025] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] According to embodiments of the present invention, an optical element damage threshold detection system is provided, such as... Figure 1 As shown, the optical component damage threshold detection system includes: First light source 1, used to output test beam.

[0027] Specifically, the test beam is used to perform damage testing on the optical component 14 under test. It is the core light source that triggers damage to the optical component and can have different parameters such as wavelength and energy. The energy of the test beam can be adjusted by the first light source 1 and / or other light intensity adjustment mechanisms.

[0028] The first light source 1 can be a single laser or a combination of multiple lasers, which outputs a test beam in a single band or multiple bands. Generally, the center wavelengths of each band of the test beam are 1064 nm, 532 nm, 355 nm, and 266 nm, etc.

[0029] The output beam of the first light source 1 can be controlled by the main controller 17 or other control devices. Preferably, the first light source 1 is connected to the main controller 17, and the main controller 17 controls the output time, light intensity and wavelength of the test beam output by the first light source 1.

[0030] The switching device includes a rotating device 6 and a driving device. The rotating device 6 is provided with multiple optical mounting positions for mounting different types of focusing optical components at intervals along the circumferential direction. The focusing optical components include single-lens focusing components and beam-shrinking focusing components. The driving device is used to drive the rotating device 6 to rotate based on the received control commands, so that any focusing optical component is located on the main optical path of the test beam.

[0031] Specifically, the center of the rotating device 6 is offset from the main optical path, and there is a point on the main optical path located on the circumference of the center of each optical mounting position. Thus, when the rotating device 6 rotates around a rotation axis parallel to the main optical path, the center of any focusing optical component can be located on the main optical path of the test beam.

[0032] The drive unit is a component that provides power to the rotating device 6, receives instructions from the main controller 17, and drives the rotating device 6 to complete precise rotation.

[0033] The main optical path is the primary propagation path of the test beam in the system. The focusing optical components and the optical element under test 14 need to be placed on the main optical path.

[0034] Optical mounting positions are located at the edge of the rotating device 6 and are spaced apart along the circumference. The spacing between adjacent optical mounting positions can be equal or unequal. Control commands to switch the center of different optical mounting positions to the main optical path can be obtained through pre-calibration.

[0035] Multiple optical mounting positions are provided for mounting different focusing optical components. These include single-lens focusing components and beam-shrinking focusing components. The single-lens focusing component can be a single focusing lens or a combination of a focusing lens and other types of lenses. The beam-shrinking focusing component can be a beam-shrinking lens or a combination of a beam-shrinking lens and other types of lenses. Due to the differences in diffraction characteristics, beam waist size, and nonlinear response in optical materials corresponding to different laser wavelengths, the single-lens focusing component is used to form laser beams with smaller spot sizes and higher peak power densities under different wavelength conditions. It is suitable for multi-wavelength damage threshold testing of thin-film optical elements and can obtain small-sized spot sizes with high spatial resolution. The beam-shrinking focusing component is used to shrink laser beams of different wavelengths. By adjusting its beam waist parameters and divergence angle, it regulates the propagation behavior of the laser within long crystals, reduces the peak power density growth rate and the effective nonlinear cumulative length, thereby suppressing the self-focusing effect. It is suitable for multi-wavelength damage threshold testing of long crystals or thick optical elements.

[0036] In addition, both the single-lens focusing assembly and the beam-shrinking focusing assembly can be set to multiple groups, each group achieving different degrees of focusing or beam shrinking. Therefore, by switching different focusing optical components, spot size compensation and self-focusing suppression can be achieved simultaneously, thus covering the dual testing needs of thin films and long crystals.

[0037] The number of optical mounting positions can be set as needed. In one example, there are two optical mounting positions, one for mounting a single-lens focusing assembly and the other for mounting a beam-shrinking focusing assembly. In another example, there are four optical mounting positions, one for mounting a single-lens focusing assembly with two different focusing effects and the other for mounting a beam-shrinking focusing assembly with two different beam-shrinking effects.

[0038] The sample stage 13 is used to set the optical element under test 14 and place the optical element under test 14 on the main optical path after the focusing optical assembly.

[0039] Specifically, the sample stage 13 is a worktable for placing and fixing the optical component 14 under test, ensuring that the component under test is stably positioned in the designated position on the main optical path of the test beam.

[0040] Imaging device 16 is used to acquire detection images of the optical element 14 under test before and after the test beam is applied.

[0041] Specifically, the imaging device 16 is a device for acquiring surface images of the optical element 14 under test. It can capture the surface state changes of the optical element 14 under test before and after the test beam is applied by acquiring detection images of the optical element 14 under test before and after the test beam is applied, thereby enabling real-time monitoring and recording of the damage state of the optical element 14 under test under the action of the test beam.

[0042] For example, the imaging device 16 may employ a CCD camera.

[0043] The main controller 17 is connected to the imaging device 16 and the driving device respectively. It is used to send corresponding control commands to the driving device according to the focusing optical components required for the current test, receive the detection images sent by the imaging device 16, and obtain the damage threshold detection results based on the analysis of the detection images.

[0044] Specifically, the main controller 17 can be a smart device with image processing capabilities, such as a computer or tablet. The main controller 17 controls the first light source 1, the switching device, and the imaging device 16 to achieve switching control of the focusing optical components, coordination of the testing process, and acquisition and processing of the detection images.

[0045] The main controller 17 controls the switching device to switch between the single lens focusing assembly and the beam shrinking lens focusing assembly according to the material type parameters of the optical material being tested, so as to realize the automatic detection of damage threshold under different material conditions.

[0046] Specifically, system calibration is required before testing. To ensure that the center of the focusing optical component is parallel to the optical axis of the main optical path, collimation is performed using low-energy probe light produced by the first light source 1. The driving device stores the rotation angle of each focusing optical component when switching to the main optical path and integrates it into the main controller 17. The main controller 17 generates corresponding control commands based on each rotation angle.

[0047] The main controller 17 determines the focusing optical component to be switched based on the material type of the different optical elements 14 under test, and outputs the corresponding control command to the drive device. The drive device controls the rotating device 6 to rotate to the corresponding rotation angle according to the control command, automatically switching the corresponding focusing optical component onto the main optical path to shape the test beam, thus achieving automatic switching between different focusing optical paths. The beam shaped by the focusing optical component is output to a specific point on the optical element 14 under test for damage testing. The imaging device 16 acquires detection images before and after the test beam's action. The main controller 17 compares the detection images before and after the test beam's action; if the images match, there is no damage; if the images do not match, damage is determined.

[0048] By pre-setting the correspondence between the rotation angle and the focusing optical components, the focusing mode can be switched quickly and stably without the need for manual adjustment of the optical components, thereby ensuring the consistency and repeatability of the optical path during the damage threshold test.

[0049] According to the optical element damage threshold detection system of the present invention, the main controller 17 can select the focusing optical component required for the current test according to the wavelength of the test beam and the type of the optical element 14 under test, and switch it to the main optical path. The beam after being shaped by the focusing optical component is output to a specific point of the optical element 14 under test for damage testing. The damage threshold detection result can be obtained by using the imaging device 16 to acquire the detection image before and after the test beam is applied. Thus, without changing the installation state of the first light source 1 and the optical element 14 under test, the focusing mode switching for different types of optical elements 14 under test can be realized. This enables the optical element damage threshold detection system to adapt to the testing requirements of thin film and long crystal optical elements, suppress long crystal self-focusing, and improve the accuracy of test results.

[0050] In some embodiments, such as Figure 2 As shown, the drive device includes a drive controller 9, a drive unit 5, and a connecting part 7. The drive controller 9 is connected to the main controller 17, and the output end of the drive unit 5 is connected to the middle part of the rotating device 6 through the connecting part 7.

[0051] Specifically, the drive unit 5 can be a high-precision servo motor, stepper motor, etc., and the drive controller 9 is a matching motor controller for controlling the operation of the corresponding motor.

[0052] The connecting part 7 is a mechanical component that connects the output end of the drive unit 5 and the rotating device 6, serving to transmit power and ensure that the power of the drive unit 5 can effectively drive the rotating device 6 to rotate. For example, the connecting part 7 can be a connecting rod, with one end connected to the rotating shaft of the drive unit 5 and the other end connected to the rotating device 6. When the drive unit 5 rotates, it can drive the rotating device 6 to rotate, allowing the rotating device 6 to switch between different preset positions. This allows different focusing optical components mounted on the rotating device 6 to selectively enter the main optical path, thereby achieving the switching of different focusing optical paths. This enables the focused test beam to adapt to different optical components under test and suppresses self-focusing of long crystals.

[0053] By directly connecting the drive controller 9 to the main controller 17, the main controller 17 can achieve precise electrical signal control of the drive device, ensuring the accurate rotation angle of the rotating device 6, so that the focusing optical component can be accurately aligned with the main optical path and improve the accuracy of optical path switching.

[0054] Furthermore, the drive device also includes a support portion 8, on which the drive unit 5 is mounted.

[0055] The support part 8 is a mechanical structure that supports and fixes the drive unit 5. It can be in the form of a bracket, base, etc., and has sufficient structural strength to ensure the stability of the drive unit 5 when it is working.

[0056] By adding a support part 8 to fix the drive unit 5, the installation stability of the drive unit 5 can be improved, and the drive unit 5 can be prevented from shaking or displacing during operation, thus ensuring the stability and continuity of power output.

[0057] In some embodiments, the rotating device 6 employs a rotating sleeve, the center of which is connected to the output end of the driving unit 5 via a connecting part 7. An optical mounting position is disposed on the rotating sleeve, and the distance from the center of the rotating sleeve to the center point of any optical mounting position is equal to the distance from the center of the rotating sleeve to the main optical path.

[0058] Specifically, driven by the drive unit 5, the rotating sleeve can rotate around a rotation axis parallel to the propagation direction of the test beam. Multiple optical mounting positions are provided on the rotating sleeve along the circumferential direction. The optical mounting positions can be slots that are adapted to the size of the focusing optical components to be installed. Different types of focusing optical components are installed on different optical mounting positions.

[0059] In this embodiment of the invention, the distances from the center of the rotating sleeve to the center point of each optical mounting position and the main optical path are all equal, so that after any focusing optical component rotates with the rotating sleeve, its optical axis can be precisely aligned with the main optical path without additional adjustment, thereby improving the accuracy and efficiency of optical path switching and avoiding problems such as beam deflection and focusing failure caused by distance deviation.

[0060] Through the above solution, the embodiments of the present invention achieve the switching of focusing modes for different types of optical elements under test without changing the installation state of the first light source 1 and the optical element under test 14, so that the same damage threshold detection system can adapt to the testing requirements of thin film and long crystal samples, and improve the versatility of the system and the consistency of test results.

[0061] In some embodiments, the optical element damage threshold detection system further includes an optical path transmission module, which is disposed between the first light source 1 and the switching device, and is used to adjust the propagation direction of the test beam so that the test beam propagates along the main optical path.

[0062] The optical path transmission module allows for more flexible installation of the first light source 1, eliminating the need for strict alignment with the main optical path, reducing the overall installation layout requirements of the system, and facilitating spatial planning and component arrangement.

[0063] By adding an optical path transmission module, the propagation direction of the test beam output by the first light source 1 can be flexibly adjusted, so that the test beam, which may originally deviate from the preset path, can be accurately adjusted to the main optical path, ensuring that the beam can be effectively transmitted to the subsequent switching device and focusing component.

[0064] Furthermore, the test beam output by the first light source 1 has multiple wavelengths. The optical path transmission module includes a first reflector 2, a second reflector 3, and a third reflector 4. The first reflector 2 is used to reflect test beams of several wavelengths to the third reflector 4. The second reflector 3 is used to reflect test beams of other wavelengths to the third reflector 4. The third reflector 4 is used to reflect the received test beam and propagate it along the main optical path. The reflection wavelengths of the first reflector 2 and the second reflector 3 are different. The reflection wavelengths of the third reflector 4 include the reflection wavelengths of the first reflector 2 and the second reflector 3.

[0065] Specifically, the type of the first light source 1 can be determined based on the required wavelength range and number of wavelengths of the test beam. The wavelength of the test beam is determined according to the laser required for the actual test.

[0066] In one example, the first light source 1 is a four-wavelength laser, outputting test beams with wavelengths of 1064 nm, 532 nm, 355 nm, and 266 nm. This laser can achieve output of 1064 nm and 532 nm lasers from the same aperture, and output of 355 nm and 266 nm lasers from the same aperture. The output spot size is approximately 10 mm, and the pulse width is 10 ns. The first reflector 2 is coated with 355 nm and 266 nm reflective films, and the second reflector 3 is coated with 1064 nm and 532 nm reflective films. The third reflector 4 is a high-reflectivity mirror coated with 1064 nm / 532 nm / 355 nm / 266 nm reflective films, with a reflection angle of 45°.

[0067] The first reflector 2 and the second reflector 3 are respectively positioned opposite to the two light-emitting holes of the first light source 1, and both the first reflector 2 and the second reflector 3 are at a 45° angle to the laser emitted from the light-emitting holes. The third reflector 4 is parallel to the first reflector 2. After the first reflector 2 and the second reflector 3 reflect the corresponding test beams to the third reflector 4, the third reflector 4 reflects them to the main optical path.

[0068] In this embodiment of the invention, considering the characteristics of multi-band test beams, a first reflecting mirror 2 and a second reflecting mirror 3 with different reflection bands are used to reflect beams of different bands respectively, and then the beams are converged to the main optical path by a third reflecting mirror 4, so as to achieve lossless and directional transmission of multi-band test beams and ensure that each band beam can propagate accurately along the main optical path.

[0069] In some embodiments, the optical element damage threshold detection system further includes a second light source 12 and a first beam splitter 11. The second light source 12 is connected to the main controller 17. The first beam splitter 11 is disposed on the main optical path and located between the focusing optical component and the optical element under test 14. The second light source 12 is used to output a detection beam to the first beam splitter 11. The first beam splitter 11 is used to reflect the detection beam to the optical element under test 14 and propagate along the main optical path.

[0070] Specifically, the light source outputting the detection beam provides imaging illumination for the imaging device 16 and is functionally distinct from the test beam, not participating in the triggering of damage to the optical element. The detection beam is used to provide illumination for the imaging device 16 and to monitor the surface condition of the optical element 14 under test. It has low energy and will not cause damage to the element under test. For example, the second light source 12 can be a semiconductor laser, outputting a detection beam with a wavelength of 633 nm.

[0071] The second light source 12 is connected to the main controller 17 to realize the automated control of the detection beam. The opening, closing and brightness of the detection beam can be adjusted according to the detection requirements to improve the flexibility of the detection.

[0072] The first beam splitter 11 can be a polarizing beam splitter (PBS), which can transmit or reflect beams with different polarization directions. By adjusting the polarization direction of the detection beam output from the second light source 12, all or part of the detection beam can be reflected by the first beam splitter 11 to the optical element under test 14 and propagate along the main optical path. At the same time, the polarization direction of the test beam output from the first light source 1 can be adjusted so that all or part of the test beam is transmitted through the first beam splitter 11 to the optical element under test 14 and continues to propagate along the main optical path.

[0073] By adding a second light source 12 and a first beam splitter 11, a detection beam is introduced, allowing the detection beam and the test beam to share the main optical path and illuminate the optical element under test 14. This enables the surface condition of the element under test to be monitored in real time through the detection beam-assisted imaging device 16 without affecting the function of the test beam, thereby improving the imaging effect.

[0074] The first beam splitter 11 reflects the detection beam to the main optical path, and the test beam can be directly transmitted, realizing the optical path merging of the two beams. There is no need to set up an additional independent detection optical path, which simplifies the system structure.

[0075] In some embodiments, the optical element damage threshold detection system further includes an optical attenuator 10, which is disposed on the main optical path and located between the focusing optical component and the first beam splitter 11.

[0076] Specifically, the optical attenuator 10 includes a half-wave plate and a polarizing beam splitter arranged sequentially along the main optical path. By rotating the angle of the half-wave plate electronically or manually, the polarization state of the test beam can be adjusted, thereby adjusting the light intensity of the test beam that can pass through the polarizing beam splitter, and realizing the energy regulation of the test beam. Different wavelengths of test beams need to be used with corresponding optical attenuators 10. When using a test beam of a certain wavelength, it is necessary to manually switch the optical attenuator 10 to the corresponding wavelength.

[0077] The test device passes through the focusing optical components, the optical attenuator 10, and the first beam splitter 11 in sequence, propagating along the main optical path.

[0078] By adding an optical attenuator 10, the energy of the test beam can be precisely adjusted to achieve the output of test beams with different energy densities, meet the energy gradient requirements for different damage threshold detection, accurately find the damage threshold of optical components, and improve the selectivity of the first light source 1 by adjusting the energy through the optical attenuator 10, which can accurately adjust the laser energy.

[0079] In some embodiments, the optical element damage threshold detection system further includes a fourth reflector 15, which is disposed between the optical element under test 14 and the imaging device 16, and is used to reflect the scattered light generated after the detection beam passes through the optical element under test 14 to the imaging device 16, and the imaging device 16 generates a detection image based on the scattered light.

[0080] Specifically, the fourth reflecting mirror 15 is an optical lens that reflects the scattered light from the surface of the optical element 14 under test. It directs the scattered light to the imaging device 16 for imaging. The damage state of the optical element 14 under test under laser action is monitored and recorded in real time by the imaging device 16 located on one side of it.

[0081] When imaging is required, the second light source 12 outputs a detection beam, which is reflected by the first beam splitter 11 and propagates to the stimulated area of ​​the optical element under test 14, so that the detection beam passes through the damage point or potential damage area of ​​the optical element under test 14. The scattered light of the optical element under test 14 is reflected by the fourth reflector 15 to the detection surface of the imaging device 16, and the imaging device 16 is used to acquire front and rear images of the scattered light.

[0082] The fourth reflector 15 makes the installation position of the imaging device 16 more flexible, without having to face the component under test, reducing the spatial layout requirements of the system and facilitating the arrangement of various components.

[0083] In some embodiments, the sample stage 13 is an electrically controlled displacement stage, which is connected to the main controller 17. The electrically controlled displacement stage is used to drive the optical element 14 under test to move in at least one direction.

[0084] Specifically, the electrically controlled displacement stage is a worktable that achieves precise displacement through electrical signal control. It is a concrete implementation of the sample stage 13 and can be equipped with drive components such as stepper motors and servo motors to achieve multi-directional, high-precision displacement adjustment. In one example, the electrically controlled displacement stage is a three-dimensional electrically controlled displacement stage. The main controller 17 can control the three-dimensional electrically controlled displacement stage to drive the optical element under test 14 to move in different directions, such as along the X-axis, Y-axis, and Z-axis, to meet different detection position adjustment requirements.

[0085] The electronically controlled displacement stage is connected to the main controller 17 to realize automated displacement control. The main controller 17 can accurately control the movement of the optical element under test 14 in at least one direction according to the detection requirements, which facilitates the detection of damage thresholds at different positions of the optical element under test 14 and obtains the overall damage resistance performance data of the optical element under test 14.

[0086] The sample stage 13 employs an electrically controlled displacement stage to achieve motorized movement of the optical component 14 under test, replacing manual movement and improving the accuracy and efficiency of component position adjustment. By driving the optical component 14 under test to adjust its position in at least one direction through the electrically controlled displacement stage, damage threshold testing of the optical component 14 at multiple points or in multiple regions can be achieved.

[0087] The embodiments of the present invention will be further described in detail below with reference to examples.

[0088] The first light source 1 uses a four-wavelength laser, outputting test beams with wavelengths of λ1, λ2, λ3, and λ4. Test beams with wavelengths of λ1 and λ2 are reflected by the first reflecting mirror 2, while those with wavelengths of λ3 and λ4 are reflected by the second reflecting mirror 3, and then by the third reflecting mirror 4 before entering the main optical path. On the main optical path, the beams sequentially pass through a single-lens focusing assembly and a beam-shrinking focusing assembly held by a switching device. After passing through the optical attenuator 10 and the first beam splitter 11, the beams strike the optical element under test 14, which is located on a three-dimensional electrically controlled displacement stage. The detection laser emitted by the second light source 12 enters the main optical path through the first beam splitter 11 and strikes the optical element under test 14. Before testing each damage point, the main controller 17 acquires an undamaged scattering pattern through the imaging device 16. After the laser test, the imaging device 16 acquires a scattering pattern after laser irradiation. The scattering patterns before and after irradiation are compared; if they match, the damage is not identified; otherwise, the damage is determined.

[0089] The four-wavelength lasers described above output wavelengths of 1064 nm, 532 nm, 355 nm, and 266 nm, respectively. This laser can achieve outputs of 1064 nm and 532 nm from the same aperture, and outputs of 355 nm and 266 nm from the same aperture. The output spot size is approximately 10 mm, and the pulse width is 10 ns. The first reflector 2 is coated with reflective films for 355 nm and 266 nm, and the second reflector 3 is coated with reflective films for 1064 nm and 532 nm. The third reflector 4 is a high-reflectivity mirror coated with films for 1064 nm / 532 nm / 355 nm / 266 nm.

[0090] The single-lens focusing assembly uses a single-focusing lens, and the beam-shrinking focusing assembly uses a beam-shrinking lens. The optical mounting positions of the rotating device 6 are respectively equipped with beam-shrinking lenses for the 1064 nm, 532 nm, and 355 nm wavelength bands, and a single-focusing lens with a focal length of 300 mm coated with anti-reflection coatings for 1064 nm / 532 nm / 355 nm / 266 nm. The combination of focusing optical components is only shown in this embodiment, but other combinations are also possible. The drive unit 5 of the driving device uses a stepper motor to drive the rotation of the rotating device 6. The drive controller 9 controls the drive unit 5, memorizes and stores the corresponding rotation angles, and is connected to the controller for overall program integration.

[0091] The second light source 12 emits a 633 nm laser beam as a detection beam, which is reflected by the first beam splitter 11 and enters the main optical path, becoming coaxial with the main optical path.

[0092] The imaging device 16 captures the scattering pattern of the detection spot before and after the laser action. The main controller 17 extracts the feature points of the before and after patterns and compares them. If the feature points are inconsistent before and after, damage is determined.

[0093] The specific procedure for detection using the optical element damage threshold detection system according to an embodiment of the present invention is as follows: S1: Test system calibration: To ensure that the optical axis center of the single lens focusing assembly and the beam shrinking lens focusing assembly is parallel to the main optical axis, the low-energy probe light produced by the first light source 1 is used for collimation, and the drive controller 9 stores the position memory and integrates it into the main controller 17.

[0094] S2: Select different test programs for different material types and test wavelengths. The main controller 17 controls the switching device to automatically switch to the corresponding single-lens focusing assembly or beam-shrinking lens focusing assembly, and manually replaces the optical attenuator 10.

[0095] S3: Place the standard sample into the sample stage 13, start the standard sample test program in the test program. After the standard sample test shows no difference in damage threshold and the program has no problems, start the sample test.

[0096] S4: The optical element under test 14 is placed on the sample stage 13, ensuring that the angle of the optical element under test 14 is the required angle for testing. The test program is started, the first light source 1 begins to generate laser, and the optical attenuator 10 begins to adjust the laser energy, starting the test from high to low or from low to high. The sample stage 13 begins to be adjusted according to the test program.

[0097] S5: If testing lasers of different wavelengths, change the test area and repeat S2-S4 to complete the testing of other wavelengths. If testing different material types, repeat S3-S4. The automatic control switching device switches the focusing optical components according to the material type. For example, to test a 10 mm long LBO crystal at 1064 nm, the focusing optical component of the switching device is adjusted to the 1064 nm beam-contraction lens. If testing the damage threshold of a 1064 nm intensifying lens, the program adjusts the focusing optical component of the switching device to a single-focusing lens.

[0098] The optical element damage threshold detection system of this invention achieves automatic switching of different focusing optical components through a switching device, avoiding manual adjustment of the optical element position and improving testing efficiency and optical path repeatability. The rotating sleeve, in conjunction with the driving device, can quickly and accurately introduce different focusing optical components into the optical path, ensuring that the beam position and focusing state remain consistent with each switch, thereby guaranteeing stable testing conditions for multiple points or multiple samples.

[0099] The system is equipped with multiple single-lens focusing components and beam-shrinking focusing components, which can provide high peak power density or low peak power density focusing methods for thin-film optical elements and long crystal / thick optical elements respectively, improving the system's versatility, while controlling the laser energy distribution, reducing unexpected damage, and improving the accuracy of damage threshold testing.

[0100] The main controller 17 provides unified control over the switching device, the movement of the sample stage 13, the triggering of the second light source 12, and the imaging detection, thereby automating the testing process and enabling synchronous data acquisition, reducing human error, and improving testing reliability and repeatability. The fixed installation of optical components, combined with the rotating sleeve for switching the optical path, also enhances the long-term stability and safety of the system.

[0101] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A damage threshold detection system for optical components, characterized in that, include: The first light source is used to output the test beam; The switching device includes a rotating device and a driving device. The rotating device is provided with multiple optical mounting positions for mounting different types of focusing optical components at intervals along the circumferential direction. The focusing optical components include single-lens focusing components and beam-shrinking focusing components. The driving device is used to drive the rotating device to rotate based on received control commands, so that any of the focusing optical components is located on the main optical path of the test beam. A sample stage is used to set up the optical element under test and position it on the main optical path after the focusing optical assembly; An imaging device is used to acquire detection images of the optical element under test before and after the test beam acts on it; The main controller is connected to the imaging device and the driving device respectively. It is used to send the corresponding control command to the driving device according to the focusing optical component required for the current test, receive the detection image sent by the imaging device, and obtain the damage threshold detection result based on the analysis of the detection image.

2. The optical element damage threshold detection system according to claim 1, characterized in that, The driving device includes a drive controller, a drive unit, and a connecting part. The drive controller is connected to the main controller, and the output end of the drive unit is connected to the middle part of the rotating device through the connecting part.

3. The optical element damage threshold detection system according to claim 2, characterized in that, The drive device also includes a support portion, and the drive unit is mounted on the support portion.

4. The optical element damage threshold detection system according to claim 2, characterized in that, The rotating device employs a rotating sleeve, the center of which is connected to the output end of the driving unit via the connecting part. The optical mounting position is disposed on the rotating sleeve, and the distance from the center of the rotating sleeve to the center point of any optical mounting position is equal to the distance from the center of the rotating sleeve to the main optical path.

5. The optical element damage threshold detection system according to claim 1, characterized in that, It also includes an optical path transmission module, which is disposed between the first light source and the switching device, and is used to adjust the propagation direction of the test beam so that the test beam propagates along the main optical path.

6. The optical element damage threshold detection system according to claim 5, characterized in that, The test beam output by the first light source has multiple wavelengths. The optical path transmission module includes a first reflector, a second reflector, and a third reflector. The first reflector is used to reflect the test beam of several wavelengths to the third reflector. The second reflector is used to reflect the test beam of the remaining wavelengths to the third reflector. The third reflector is used to reflect the received test beam and propagate it along the main optical path. The reflection wavelengths of the first reflector and the second reflector are different. The reflection wavelength of the third reflector includes the reflection wavelengths of the first reflector and the second reflector.

7. The optical element damage threshold detection system according to claim 1, characterized in that, It also includes a second light source and a first beam splitter. The second light source is connected to the main controller. The first beam splitter is disposed on the main optical path and located between the focusing optical component and the optical element under test. The second light source is used to output a detection beam to the first beam splitter. The first beam splitter is used to reflect the detection beam to the optical element under test and propagate along the main optical path.

8. The optical element damage threshold detection system according to claim 7, characterized in that, It also includes an optical attenuator, which is disposed on the main optical path and located between the focusing optical component and the first beam splitter.

9. The optical element damage threshold detection system according to claim 7, characterized in that, It also includes a fourth reflecting mirror, which is disposed between the optical element under test and the imaging device, for reflecting the scattered light generated after the detection beam passes through the optical element under test to the imaging device, and the imaging device generates the detection image based on the scattered light.

10. The optical element damage threshold detection system according to claim 1, characterized in that, The sample stage is an electrically controlled displacement stage, which is connected to the main controller. The electrically controlled displacement stage is used to drive the optical element under test to move in at least one direction.

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