A system and method for non-destructive testing of surface thermal sensitivity defects of an optical element

Abstract

The application discloses a kind of optical element surface thermosensitive defect nondestructive testing system and method, wherein optical element surface thermosensitive defect nondestructive testing system includes optical coherence tomography device, laser pumping device and signal processing and control module.The above technical scheme is used to a kind of optical element surface thermosensitive defect nondestructive testing system and method, utilizes laser pumping cooperation optical coherence tomography, realizes the rapid detection to optical element surface thermosensitive defect, possesses fast, nondestructive, micron level high-resolution structure imaging, nanometer level high-precision phase detection and so on Advantage, break through the technical bottleneck of traditional thermosensitive defect detection means " detection precision and detection efficiency cannot be obtained simultaneously ", simultaneously can gather the three-dimensional structure image and phase information of optical element, so as to obtain the accurate three-dimensional position information of thermosensitive defect in optical element including depth position information.

Description

Technical Field

[0001] This invention relates to the field of industrial imaging technology, and more specifically to a non-destructive testing system and method for thermally sensitive defects on the surface of optical components. Background Technology

[0002] High-energy, high-power laser devices contain numerous functional optical components with high transmission, high reflection, and polarization beam splitting capabilities. When thermally sensitive defects exist in the optical matrix material or surface thin film, they strongly absorb the transmitted laser energy and convert it into heat through photoelectric or photoacoustic effects. Once the temperature rise or stress generated by this thermal field effect exceeds the tolerance limit of the optical material, laser-induced damage to the optical components can occur. Therefore, detecting thermally sensitive defects in in-service optical components is of great significance for evaluating the manufacturing process level of optical components and ensuring the stable operation of high-energy laser systems.

[0003] Thermosensitive defects mainly originate from absorbing impurities, scratches, microcracks, and nodule defects in the film layer introduced during the polishing or coating process of the component surface, exhibiting a micro-mesoscopic distribution characteristic ranging from submicrometers to millimeters. While photothermal weak absorption detection technology based on the photothermal deflection principle boasts high sensitivity, it is limited by a single-point test area ≤50μm. For optical components with dimensions ≥100mm, achieving full-aperture coverage detection can take several days. Therefore, existing technologies suffer from a technical deficiency where detection efficiency and accuracy cannot be simultaneously achieved when performing full-aperture coverage detection on large-aperture optical components.

[0004] Please refer to Chinese patent application CN116297527A, in which the applicant proposed a method for rapidly detecting the distribution of thermally sensitive defects on the surface of optical components. Specifically, it relates to the field of precision detection technology for optical components and includes the following steps: design of a laser continuous pumping system, design of a micro-area interferometric microscopy imaging system, and design of an automatic control and data acquisition system. This method can complete the rapid, highly sensitive, and high-resolution detection of thermally sensitive defects on the surface of 100mm diameter optical components within a few hours, breaking through the technical bottleneck of traditional thermally sensitive defect detection methods where "detection accuracy and detection efficiency cannot be achieved simultaneously".

[0005] However, in practical applications, the applicant found that the detection time was still too long, and the above method could not perform three-dimensional imaging of optical components, thus failing to accurately determine the depth and location information of thermally sensitive defects.

[0006] Solving these problems is now a top priority. Summary of the Invention

[0007] To address the technical problems of low detection efficiency and inability to accurately determine the depth and location of thermally sensitive defects on the surface of existing optical components, this invention provides a non-destructive testing system and method for thermally sensitive defects on the surface of optical components.

[0008] The technical solution is as follows:

[0009] A non-destructive testing system for thermally sensitive defects on the surface of an optical element, characterized in that it includes an optical coherence tomography device, a laser pumping device, and a signal processing and control module, wherein the optical element under test is mounted on a multi-dimensional translation stage, and the laser pumping device is used to excite the photothermal effect of thermally sensitive defects on the surface of the optical element under test.

[0010] The optical coherence tomography device includes a light source, a beam splitter assembly, a signal recording assembly, a reference optical path, and an optical element optical path;

[0011] The reference optical path includes a reference optical path polarization controller, a reference optical path collimator, a reference optical path focusing lens, and a reference optical path reflector arranged sequentially in the direction away from the beam splitter;

[0012] The optical path of the optical element includes an optical path polarization controller, an optical path collimator, a scanning component, and a scanning lens, which are sequentially arranged between the beam splitter and the optical element under test.

[0013] A non-destructive testing method for thermally sensitive defects on the surface of optical components, employing the aforementioned non-destructive testing system for thermally sensitive defects on the surface of optical components, is carried out according to the following steps:

[0014] S1. Start the multi-dimensional translation stage and change the position of the optical element under test;

[0015] S2. The laser pumping device remains off, the optical coherence tomography device is started once, the original optical coherence tomography signal is acquired, and transmitted to the signal processing and control module.

[0016] S3. The laser pumping device remains on, and the optical coherence tomography device is activated once to acquire the laser pumped optical coherence tomography signal and transmit it to the signal processing and control module.

[0017] S4. Return to step S1 until the full aperture range of the optical element under test is scanned;

[0018] S5. The signal processing and control module performs Fourier transform on the acquired signals to obtain three-dimensional structural images and phase data.

[0019] S6. The surface thermal-sensitive defect distribution of the optical element under test is obtained based on the three-dimensional structural image and phase data.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] A non-destructive testing system and method for thermally sensitive defects on the surface of optical components, employing the above technical solution, utilizes laser pumping combined with optical coherence tomography to achieve rapid detection of thermally sensitive defects on the surface of optical components. It has advantages such as being fast, non-destructive, providing micron-level high-resolution structural imaging, and nanometer-level high-precision phase detection. It breaks through the technical bottleneck of traditional thermally sensitive defect detection methods where "detection accuracy and detection efficiency cannot be simultaneously achieved." At the same time, it can acquire three-dimensional structural images and phase information of optical components, thereby obtaining precise three-dimensional position information of thermally sensitive defects in optical components, including depth position information. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a non-destructive testing system for thermally sensitive defects on the surface of optical components.

[0023] Figure 2 This is a schematic diagram of an optical coherence tomography (OCT) device. Detailed Implementation

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

[0025] In this embodiment, the measurement space of the optical element under test 21 is represented by three-dimensional xyz coordinates based on spatial direction. This description is only for facilitating discussion and is not intended to limit the application of the embodiments of the present invention. Wherein: the depth z direction is the direction along the incident optical axis; the xy plane is a plane perpendicular to the optical axis, where x and y are orthogonal, and x represents the lateral fast scan direction of optical coherence tomography, and y represents the lateral slow scan direction of optical coherence tomography.

[0026] like Figure 1 and Figure 2 As shown, a non-destructive testing system for thermally sensitive defects on the surface of optical components mainly includes an optical coherence tomography device, a laser pumping device, and a signal processing and control module 45.

[0027] The optical element under test 21 is mounted on a multi-dimensional translation stage 55 to adjust its position. When the multi-dimensional translation stage 55 is an electric two-dimensional translation stage, it can adjust the planar position of the optical element under test 21; when the multi-dimensional translation stage 55 is an electric three-dimensional translation stage, it can adjust the spatial position of the optical element under test 21.

[0028] The optical coherence tomography device mainly includes a light source 11, a beam splitter 12, a signal recording component 22, a reference optical path, and an optical element optical path.

[0029] The reference optical path includes a reference optical path polarization controller 13, a reference optical path collimator 14, a reference optical path focusing lens 15, and a reference optical path reflector 16, arranged sequentially in the direction away from the beam splitter assembly 12. The optical element optical path includes an element optical path polarization controller 17, an element optical path collimator 18, a scanning assembly 19, and a scanning lens 20, arranged sequentially between the beam splitter assembly 12 and the optical element under test 21.

[0030] Therefore, in the optical coherence tomography apparatus of this embodiment, the light emitted from the light source 11 is split into two by the beam splitter 12; one beam enters the reference optical path, is first polarized by the reference optical path polarization controller 13, then collimated by the reference optical path collimator 14, and finally focused on the reference optical path mirror 16 by the reference optical path focusing lens 15; the other beam enters the optical element optical path, is first polarized by the element optical path polarization controller 17, then collimated by the element optical path collimator 18, then adjusted by the scanning assembly 19, and finally focused on the optical element 21 under test by the scanning lens 20; the light reflected by the reference optical path mirror 16 and the backscattered light from the optical element 21 under test interfere at the beam splitter 12, and is recorded by the signal recording assembly 22, which then transmits the signal to the signal processing and control module 45, which analyzes and processes the signal.

[0031] The laser pumping device is used to excite the photothermal effect of the thermosensitive defects on the surface of the optical element under test 21. Therefore, when the optical element under test 21 changes position under the control of the multi-dimensional translation stage 55, the light source 11 emits light twice. When the first light is focused on the optical element under test 21, the laser pumping device does not excite the photothermal effect of the thermosensitive defects on the surface of the optical element under test 21, and the original optical coherence tomography interference signal is obtained. When the second light is focused on the optical element under test 21, the laser pumping device excites the photothermal effect of the thermosensitive defects on the surface of the optical element under test 21, and the laser pumped optical coherence tomography interference signal is obtained.

[0032] It should be noted that the laser pumping device performs uniform high-intensity laser pumping on the surface of the optical element 21 under test. More specifically, the wavelength of the pump light emitted by the laser pumping device is the same as or close to the application wavelength of the optical element 21 under test. The spot of the pump light emitted by the laser pumping device is flat-topped and uniformly distributed, and the size of the spot is the same as the field of view of optical coherence tomography, thereby achieving uniform illumination of the surface of the optical element 21 under test and exciting the photothermal effect. Among them, the pump laser 53 is preferably a continuous pump laser or a pulsed pump laser, so as to ensure uniform high-intensity laser pumping on the surface of the optical element 21 under test.

[0033] In this embodiment, the optical coherence tomography imaging device has the following three implementations:

[0034] Example 1 of the optical coherence tomography apparatus: The light source 11 is a low-coherence light source, and the signal recording component 22 is a detector. Example 1 of the optical coherence tomography apparatus is a time-domain measurement device. The light source 11 uses broadband low-coherence light, the reference optical path reflector 16 is movable along the optical axis, and the signal recording component 22 is a point detector. By moving the reference optical path reflector 16 to change the optical path length of the reference arm, the interference signal of the two optical paths is detected by the point detector, realizing low-coherence interference detection of the scattered signal in the spatial depth z direction of the optical element 21 under test, thereby obtaining a depth-resolved optical coherence tomography sampling volume.

[0035] Example 2 of the optical coherence tomography device: The light source 11 is a low-coherence light source, and the signal recording component 22 is a spectrometer. Example 2 of the optical coherence tomography device is a spectral domain measurement device. The light source 11 uses broadband low-coherence light, the reference optical path reflector 16 is fixed, and the signal recording component 22 is a spectrometer. The high-speed linear array camera 22d in the spectrometer simultaneously detects the interference signal along the depth direction at a certain position of the optical element 21 under test. The interference spectral signal is analyzed using the Fourier transform method, and the scattering information along the depth z direction of the optical element 21 under test is acquired in parallel, thereby obtaining a depth-resolved optical coherence tomography sampling volume.

[0036] Example 3 of the optical coherence tomography (OCT) device: The light source 11 is a swept broadband light source, and the signal recording component 22 is a detector. Example 3 of the OCT device is a swept frequency measurement device. The light source 11 is a swept broadband light source, the reference optical path reflector 16 is fixed, and the optical element under test 21 is a point detector. The point detector records the low-coherence interference spectrum of the swept broadband light source in a time-division manner. The interference spectrum signal is analyzed using the Fourier transform method, and the scattering information in the depth z direction is acquired in parallel, thereby obtaining a depth-resolved OCT sample volume.

[0037] The following non-destructive testing system for thermally sensitive defects on the surface of optical components uses an optical coherence tomography device as an example (Example 2):

[0038] Light source 11 is a low-coherence light source. The beam splitting assembly 12 includes an optical circulator 12a and an optical fiber coupler 12b connected by optical fibers. The light emitted from the low-coherence light source is transmitted to the optical circulator 12a through the optical fiber. A dispersion compensator 48 is disposed between the reference optical path collimator 14 and the reference optical path focusing lens 15. An objective lens 39, a focusing lens 49, and a dichroic mirror 50 are disposed sequentially between the scanning assembly 19 and the scanning lens 20. The signal recording assembly 22 is a spectrometer, which includes a third optical fiber collimator 22a and a grating disposed sequentially. 22b, Fourier transform lens 22c, and high-speed linear array camera 22d; optical circulator 12a is connected to third fiber collimator 22a via optical fiber; high-speed linear array camera 22d can transmit the acquired signal to signal processing and control module 45; laser pumping device includes pump laser 53 and beam shaping module 54; pump light emitted from pump laser 53 is shaped by beam shaping module 54 and focused onto optical element 21 under test; signal processing and control module 45 can control pump laser 53 and multidimensional translation stage 55.

[0039] Among them, the low coherence light source is a superluminescent diode light source with a center wavelength of 1325nm and a bandwidth of 100nm, the high-speed linear array camera 22d is a linear array scanning camera composed of 2048 pixel units, the scanning lens 20 is a lens with a focal length of 54mm, the scanning component 19 is a scanning galvanometer, and the reference optical path collimator 14 and the component optical path collimator 18 are both fiber collimators.

[0040] Light emitted from a low-coherence source passes through an optical circulator 12a and then enters a fiber coupler 12b with a splitting ratio of 50:50. The light exiting the fiber coupler 12b is split into two beams: one beam travels through an optical fiber to a reference optical path collimator 14 via a reference optical path polarization controller 13, and then passes through collimation, dispersion compensation by a dispersion compensator 48, and focusing by a reference optical path focusing lens 15 before illuminating a reference optical path reflector 16; the other beam travels through an optical fiber to an element optical path collimator 18 via an element optical path polarization controller 17, and then passes through collimation, reflection by a scanning assembly 19 (scanning galvanometer), objective lens 39, focusing lens 49, dichroic mirror 50, and scanning lens 20 before illuminating the optical element under test 21. Before the scanning lens 20, a dichroic mirror 50 is used to bend the light emitted from the focusing lens 49 by 90° in the element optical path. The scanning mirror in the component optical path is fixed, enabling the low-coherence interferometer to detect the scattering signals in the depth direction at the same spatial location of the optical element under test 21 at different times in parallel. Simultaneously, the beam transmitted through the single-mode fiber in the component optical path acts as a spatial filter for the light scattered back from the optical element under test 21, effectively reducing the multiple scattering components in the scattering signal. The light reflected by the reference optical path mirror 16 in the reference optical path interferes with the backscattered light from the optical element under test 21 in the component optical path at the fiber coupler 12b. The interference light is detected and recorded by a spectrometer (including a third fiber collimator 22a, a grating 22b, a Fourier transform lens 22c, and a high-speed linear array camera 22d), and then acquired and analyzed by the signal processing and control module 45.

[0041] The signal processing and control module 45 can also control the multi-dimensional translation stage 55 and the output control unit of the pump laser 53. During actual testing, the multi-dimensional translation stage 55 moves in steps in the x and y directions according to the programmed coordinates and path. The step size matches the optical coherence tomography (OCT) field of view. Each step involves the output control unit of the pump laser 53 shutting off the laser output and acquiring the original OCT interference signal of the optical element under unpumped conditions. Then, the output shutter of the pump laser 53 is opened, and the laser-pumped OCT interference signal of the optical element 21 under laser output conditions is acquired again. By combining step scanning with image stitching, the two-dimensional distribution and relative change information of thermal defects across the entire aperture range of the optical element can be obtained. This information is used to evaluate the defect control level on the surface of the optical element 21 under test and to predict the element's resistance to laser damage under strong laser loading. The following Example 2 illustrates the specific method:

[0042] Example 2

[0043] A non-destructive testing method for thermally sensitive defects on the surface of optical components, using the non-destructive testing system for thermally sensitive defects on the surface of optical components described in Example 1, is performed according to the following steps:

[0044] S1. Start the multi-dimensional translation stage 55 to change the position of the optical element 21 under test.

[0045] S2. The laser pumping device remains off, the optical coherence tomography device is started once, the original optical coherence tomography signal is acquired, and transmitted to the signal processing and control module 45.

[0046] S3. The laser pumping device remains on, and the optical coherence tomography device is activated once to acquire the laser-pumped optical coherence tomography signal and transmit it to the signal processing and control module 45.

[0047] S4. Return to step S1 until the optical element under test 21 has completed scanning across its entire aperture range.

[0048] S5, the signal processing and control module 45, performs Fourier transform on the acquired signals to obtain three-dimensional structural images and phase data.

[0049] S6. The surface thermal-sensitive defect distribution of the optical element 21 under test is extracted based on the three-dimensional structural image and phase data, specifically according to the following steps:

[0050] S61. Based on the design parameters of the surface boundary of the optical element under test 21, the preset pixel width is vertically extended to both sides to create the surface boundary constraint region of the optical element under test 21 and generate the surface boundary mask of the optical element under test 21.

[0051] S62. Extract the surface boundary pixel positions of the optical element under test 21 in the three-dimensional structural image of optical coherence tomography using a surface boundary mask of the optical element under test 21. In this step, the interference of strong reflection artifacts at the boundary in the image is suppressed by using a three-dimensional boundary mask of the optical element under test 21, and the surface boundary pixel positions of the optical element under test 21 in the three-dimensional structural image of optical coherence tomography are extracted. The extraction of the surface boundary pixel positions is based on the shortest path of graph search.

[0052] S63. Correct the pixel position of the surface boundary of the optical element under test 21 using the energy centroid method. In this step, the pixel position is determined based on the axial position z of the surface boundary of the optical element. m Nearby discrete point z m-n Pixel to z m+n The pixel intensity is calculated using data fitting to determine the sub-pixel position of the peak value within the surface boundary envelope, where the boundary axial position z is used. m The intensity of the n pixels before and after the given value is used to calculate the sub-pixel position z0 at the boundary. The formula for calculating sub-pixel precision ranging is as follows:

[0053]

[0054] Among them, gm+k For z m The intensity of nearby pixels, z m+k is the location of a nearby pixel, and k is the axial position index of the surface boundary of the optical element 21 under test.

[0055] S64. Based on the pixel positions of the surface boundaries of the optical element under test 21, the phase data of optical coherence tomography is unwrapped to restore the original phase data of the surface boundary positions of the optical element under test 21, and the surface thermally sensitive defect distribution is generated based on the phase information. This step S64 is performed according to the following steps:

[0056] S641. At the sub-pixel position of the surface boundary of each optical element under test 21, calculate the difference in the surface boundary deformation phase signal of the optical element under test 21 before and after the pump laser loading.

[0057] S642. Process the phase difference of the reference signal before and after the surface boundary deformation of the optical element 21 under test as the phase change of the reference signal.

[0058] S643. The phase difference of the surface boundary of the optical element under test 21 is compensated by the phase change of the reference signal;

[0059] S644. The phase difference of the surface boundary of the compensated optical element 21 under test is converted into deformation to reflect the relative light absorption intensity of the thermally sensitive defect, generating the surface thermally sensitive defect distribution and realizing the nanometer-level precision detection of the surface thermally sensitive defect.

[0060] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention. Those skilled in the art, under the guidance of the present invention, can make various similar representations without departing from the spirit and claims of the present invention, and such modifications all fall within the protection scope of the present invention.

Claims

1. A non-destructive testing method for thermally sensitive defects on the surface of optical components, characterized in that, A non-destructive testing system for thermally sensitive defects on the surface of optical components is adopted. The system includes an optical coherence tomography device, a laser pumping device, and a signal processing and control module. The optical component under test is mounted on a multi-dimensional translation stage, and the laser pumping device is used to excite the photothermal effect of the thermally sensitive defects on the surface of the optical component under test. The optical coherence tomography device includes a light source, a beam splitter assembly, a signal recording assembly, a reference optical path, and an optical element optical path; The reference optical path includes a reference optical path polarization controller, a reference optical path collimator, a reference optical path focusing lens, and a reference optical path reflector arranged sequentially in the direction away from the beam splitter; The optical path of the optical element includes an optical path polarization controller, an optical path collimator, a scanning component, and a scanning lens, which are sequentially arranged between the beam splitter and the optical element under test. The non-destructive testing method for thermally sensitive defects on the surface of optical components is performed according to the following steps: S1. Start the multi-dimensional translation stage and change the position of the optical element under test; S2. The laser pumping device remains off, the optical coherence tomography device is started once, the original optical coherence tomography signal is acquired, and transmitted to the signal processing and control module. S3. The laser pumping device remains on, and the optical coherence tomography device is activated once to acquire the laser pumped optical coherence tomography signal and transmit it to the signal processing and control module. S4. Return to step S1 until the full aperture range of the optical element under test is scanned; S5. The signal processing and control module performs Fourier transform on the acquired signals to obtain three-dimensional structural images and phase data. S6. The surface thermal-sensitive defect distribution of the optical element under test is extracted based on the three-dimensional structural image and phase data. Step S6 is performed according to the following steps: S61. Based on the design parameters of the surface boundary of the optical element under test, the preset pixel width is vertically extended to both sides to create the surface boundary constraint region of the optical element under test and generate the surface boundary mask of the optical element under test. S62. Extract the pixel positions of the surface boundary of the optical element under test in the three-dimensional structural image of optical coherence tomography using the surface boundary mask of the optical element under test. S63. Correct the surface boundary pixel position of the optical element under test using the energy centroid method; S64. Based on the pixel position of the surface boundary of the optical element under test, the phase data of optical coherence tomography is unwrapped to restore the original phase data of the surface boundary position of the optical element under test, and the distribution of surface thermally sensitive defects is generated based on the phase information.

2. The non-destructive testing method for thermally sensitive defects on the surface of optical components according to claim 1, characterized in that, In step S62, the interference of strong reflection artifacts at the boundary in the image is suppressed by using a three-dimensional boundary mask of the optical element under test, and the surface boundary pixel position of the optical element under test in the three-dimensional structural image of optical coherence tomography is extracted. The extraction of the surface boundary pixel position is based on the shortest path of graph search.

3. The non-destructive testing method for thermally sensitive defects on the surface of optical components according to claim 1, characterized in that, In step S63, the axial position z of the optical element surface boundary is used as the basis. m Nearby discrete point z m-n Pixel to z m+n The pixel intensity is calculated using data fitting to determine the sub-pixel position of the peak value within the surface boundary envelope, where the boundary axial position z is used. m Given the intensity of the n pixels before and after the given value, calculate the sub-pixel position z0 at the boundary. The formula for calculating this sub-pixel precision ranging is as follows: ； in, for The intensity of nearby pixels, is the location of a nearby pixel, and k is the axial position index of the boundary of the surface of the optical element under test.

4. The non-destructive testing method for thermally sensitive defects on the surface of optical components according to claim 1, characterized in that, Step S64 is performed according to the following steps: S641. At the sub-pixel position of the surface boundary of each optical element under test, calculate the difference in the surface boundary deformation phase signal of the optical element under test before and after the pump laser loading. S642. Process the phase difference of the reference signal before and after the surface boundary deformation of the optical element under test as the phase change of the reference signal. S643. Compensate for the phase difference of the surface boundary of the optical element under test by using the phase change of the reference signal; S644. Convert the phase difference of the surface boundary of the compensated optical element under test into deformation to generate the surface thermal sensitivity defect distribution.

5. The non-destructive testing method for thermally sensitive defects on the surface of optical components according to claim 1, characterized in that, In step S3, the wavelength of the pump light emitted by the laser pumping device is the same as the application wavelength of the optical element under test, the spot of the pump light emitted by the laser pumping device is flat-topped and uniformly distributed, and the size of the spot is the same as the field of view of optical coherence tomography.

6. The non-destructive testing method for thermally sensitive defects on the surface of optical components according to claim 1, characterized in that: The light source is a low-coherence light source or a swept-bandwidth spectral light source; when the light source is a low-coherence light source, the signal recording component is a detector or a spectrometer; when the light source is a swept-bandwidth spectral light source, the signal recording component is a detector.

7. The non-destructive testing method for thermally sensitive defects on the surface of optical components according to claim 1, characterized in that: The light source is a low-coherence light source. The beam splitting assembly includes an optical circulator and an optical coupler connected by optical fibers. The light emitted from the low-coherence light source is transmitted to the optical circulator through optical fibers. A dispersion compensator is provided between the reference optical path collimator and the reference optical path focusing lens. An objective lens, a focusing lens, and a dichroic mirror are sequentially arranged between the scanning assembly and the scanning lens. The signal recording assembly is a spectrometer, which includes a third optical fiber collimator, a grating, a Fourier transform lens, and a high-speed linear array camera arranged sequentially. The optical circulator is connected to the third optical fiber collimator through optical fibers. The high-speed linear array camera can transmit the acquired signal to the signal processing and control module. The laser pumping device includes a pump laser and a beam shaping module. The pump light emitted from the pump laser is shaped by the beam shaping module and focused onto the optical element under test. The signal processing and control module can control the pump laser and the multi-dimensional translation stage.

8. The non-destructive testing method for thermally sensitive defects on the surface of optical components according to claim 7, characterized in that: The pump laser is a continuous-pump laser or a pulsed-pump laser.

Images