Wavefront debugging and detecting device for laser beam expanding lens

Abstract

The utility model discloses a wavefront debugging and detecting device for a laser beam-expanding lens, which is used for debugging and detecting a laser beam-expanding lens to be detected and comprises a laser light source part, a standard laser beam-expanding lens, a pinhole diaphragm and a shearing interferometer which are sequentially arranged and are coaxial at equal height, and the laser beam-expanding lens to be detected is arranged between the pinhole diaphragm and the shearing interferometer. The laser light source part is used as a standard laser light source, the standard laser beam expanding lens is used for expanding the standard laser light source to an entrance pupil size matched with that of the laser beam expanding lens to be measured, and the small-hole diaphragm is used for limiting the spot diameter of the standard laser light source entering the laser beam expanding lens to be measured; and the shearing interferometer is used for testing the wavefront of the standard laser light source after passing through the to-be-tested laser beam expanding lens. According to the utility model, the laser light source piece, the standard lens and the shearing interferometer are utilized, the wavefront debugging precision is improved, and the wavefront aberration is reduced by observing interference fringes in real time and finely adjusting the lens and guiding lens installation and stress release, so that the problem that the beam expanding multiple is reduced is solved.

Description

Technical Field

[0001] This utility model relates to the field of optical detection technology, and in particular to a laser beam expander wavefront adjustment and detection device. Background Technology

[0002] In the high-precision field of laser guidance, laser illuminators play a crucial role as core optoelectronic devices that work in conjunction with various laser-guided missiles and artillery shells to achieve precise target strikes. Among these, the development of the laser source is of paramount importance. Currently, pulsed solid-state lasers with 1064nm output achieved using LD-pumped Nd:YAG crystal electro-optic Q-switching technology remain the mainstream technology for laser illuminators due to their superior performance.

[0003] However, depending on the operating distance of different mounting platforms, the beam divergence angle of the laser illuminator must be strictly controlled within the range of 0.1 mrad to 0.3 mrad after collimation and amplification by the beam expander lens. Since the original beam divergence angle of an electro-optic Q-switched pulsed solid-state laser is typically between 1 mrad and 2 mrad, compressing it to the specified range usually requires beam expansion by a factor of 5 to 15. This not only necessitates that the laser beam expander be designed to meet stringent wavefront requirements, but also that the lens assembly and adjustment errors be minimized to ensure that the wavefront aberration of the laser beam after passing through the beam expander lens is as close as possible to the theoretical design value.

[0004] However, during actual assembly and adjustment, the error of the beam expander lens is difficult to quantify and control, resulting in an actual beam expansion ratio far lower than the theoretical design value. This significantly reduces the beam expansion effect, and the laser beam divergence angle fails to meet the predetermined standard. This problem is particularly severe for high-end products such as airborne laser illuminators that require a beam divergence angle of less than 0.2 mrad. Large lens adjustment errors, low beam expansion ratios, and large laser beam divergence angles directly weaken ranging and illumination capabilities, thereby affecting the performance of the entire laser guidance system. Utility Model Content

[0005] In view of this, the present invention addresses the deficiencies of the existing technology and its main purpose is to provide a laser beam expander wavefront adjustment and testing device. This device solves the technical problem that it is difficult to quantify and control the error during the installation and adjustment of the laser beam expander, resulting in the actual beam expansion ratio being far lower than the theoretical design value, making it difficult to meet the strict requirements of the laser measuring instrument for the laser beam divergence angle.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention discloses a laser beam expander wavefront adjustment and testing device for adjusting and testing a laser beam expander under test. It includes a laser source element, a standard laser beam expander, a pinhole aperture, and a shearing interferometer, all coaxial and at the same height. The laser source element emits a standard laser source, which serves as the standard source for the adjustment and testing device. The standard laser beam expander is positioned at the emitting end of the laser source element to expand the standard laser source beam to an entrance pupil size matching that of the laser beam expander under test. The pinhole aperture is positioned in the output optical path of the standard laser beam expander to limit the spot diameter of the standard laser source entering the laser beam expander under test, ensuring that the spot diameter matches the entrance pupil size of the laser beam expander under test. The laser beam expander under test is positioned at the emitting end of the pinhole aperture. The shearing interferometer is positioned in the output optical path of the laser beam expander under test to test the wavefront of the standard laser source after passing through the laser beam expander under test.

[0008] As a preferred embodiment, the laser source is a high beam quality 1064nm pulsed solid-state laser with fundamental mode output.

[0009] As a preferred embodiment, the single-pulse energy of the laser source is 10 mJ.

[0010] As a preferred embodiment, the diameter of the spot of the standard laser light source emitted by the laser light source is 1 mm.

[0011] As a preferred embodiment, the beam expansion factor of the standard laser beam expander is 3 to 8, and the design wavelength of the standard laser beam expander is 1064 nm.

[0012] As a preferred embodiment, the distance between the laser source and the pinhole aperture is not less than 3m.

[0013] As a preferred embodiment, the laser beam expander under test includes a lens barrel, an objective lens assembly, and an adjustable eyepiece assembly. The adjustable eyepiece assembly is mounted on one end of the lens barrel near the pinhole aperture via adjustable fasteners, and the objective lens assembly is mounted on the other end of the lens barrel.

[0014] As a preferred embodiment, the adjustable eyepiece assembly includes an eyepiece mounting housing, an eyepiece element, and an adjustable washer. The end of the lens barrel furthest from the objective lens assembly has a mounting groove. The eyepiece mounting housing is placed in the mounting groove. A mounting cavity is formed on the side of the eyepiece mounting housing near the pinhole diaphragm. The eyepiece element is installed in the mounting cavity. A light-transmitting hole is formed on the side of the mounting cavity near the objective lens assembly, passing through the mounting groove and communicating with the lens barrel. A mounting protrusion is formed on the end of the eyepiece mounting housing furthest from the objective lens assembly. The mounting protrusion has a fastening mounting hole adapted to the adjustable fastener. The adjustable washer is sleeved on the eyepiece mounting housing and located between the mounting protrusion and the lens barrel for adjusting the focal length.

[0015] As a preferred embodiment, the distance between the adjustable washer and the pinhole aperture is 5mm to 15mm, and the thickness of the adjustable washer is 0.5mm to 1mm.

[0016] As a preferred option, it also includes:

[0017] An adjustable platform is provided, wherein the laser source is mounted on the adjustable platform, and the adjustable platform is used to adjust the emission direction of the laser source.

[0018] An optical platform is located beside the adjustable platform, and the standard laser beam expander, pinhole aperture, laser beam expander under test, and shearing interferometer are all sequentially and adjustablely mounted on the optical platform.

[0019] Compared with the prior art, this utility model has significant advantages and beneficial effects. Specifically, as can be seen from the above technical solution, it mainly utilizes a laser source, a standard laser beam expander lens, and a shearing interferometer to significantly improve the wavefront adjustment accuracy. Furthermore, through the visualization information of the shearing interferometer, interference fringes can be observed in real time and the laser beam expander lens under test can be finely adjusted. This provides accurate feedback on the problems presented by the laser beam expander lens under test during the adjustment process, thereby guiding the installation and stress release of the lens, realizing quantifiable adjustment of the wavefront, minimizing wavefront aberrations, effectively solving the problem of reduced beam expansion ratio caused by improper installation, improving the overall performance of the laser measuring instrument, and meeting the strict requirements of the laser measuring instrument for laser beam divergence angle.

[0020] To more clearly illustrate the structural features and effects of this utility model, the following detailed description of this utility model is provided in conjunction with the accompanying drawings and specific embodiments. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structural principle of the laser beam expander wavefront adjustment and detection device according to an embodiment of this application;

[0022] Figure 2This is a schematic diagram of the structure of the laser beam expander lens under test according to an embodiment of this application;

[0023] Figure 3 This is a cross-sectional view of the laser beam expander lens under test according to an embodiment of this application;

[0024] Figure 4 This is a schematic diagram of the installation position of the laser beam expander lens under test on the laser measuring device, according to an embodiment of this application.

[0025] Explanation of reference numerals in the attached figures:

[0026] 10. Laser light source components;

[0027] 20. Standard laser beam expander lens;

[0028] 30. Small aperture;

[0029] 40. Laser beam expander lens under test; 41. Lens barrel; 411. Mounting slot; 42. Objective lens assembly; 43. Adjustable eyepiece assembly; 431. Eyepiece mounting housing; 432. Eyepiece component; 433. Adjustable washer; 434. Mounting cavity; 435. Light passage; 436. Mounting ring; 437. Fastening mounting hole; 44. Adjustable fastener;

[0030] 50. Shearing interferometer;

[0031] 60. Wedge lens assembly;

[0032] 70. Laser output window. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the scope of the present utility model.

[0034] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0035] Please see Figures 1 to 4This utility model provides a laser beam expander wavefront adjustment and testing device for adjusting and testing a laser beam expander 40 under test. It includes a laser source element 10, a standard laser beam expander 20, a pinhole aperture 30, and a shearing interferometer 50, all coaxial and at the same height. The laser source element 10 emits a standard laser source, providing stable and high-quality light source input to ensure the accuracy of the adjustment process. The standard laser beam expander 20 is located at the emitting end of the laser source element 10 and expands the standard laser source beam to an entrance pupil size matching that of the laser beam expander 40 under test, ensuring that the laser beam can adapt to the entrance pupil of the lens under test, providing a basis for subsequent adjustment. The pinhole aperture 30 is located in the output optical path of the standard laser beam expander 20 and limits the spot diameter of the standard laser source entering the laser beam expander 40 under test, ensuring that the spot diameter of the standard laser source entering the laser beam expander 40 under test matches the entrance pupil size of the laser beam expander 40 under test, further ensuring the accuracy and adaptability of the laser beam. The laser beam expander lens 40 under test is positioned at the output end of the pinhole aperture 30. As the core object for debugging and testing, the precise expansion and wavefront optimization of the laser beam are achieved through the adjustment of this lens. The shearing interferometer 50 is positioned in the output optical path of the laser beam expander lens 40 under test. It is used to test the wavefront of a standard laser source after passing through the laser beam expander lens 40. By observing the shape and distribution of the interference fringes, the wavefront performance of the lens under test is accurately determined, providing important data for subsequent debugging.

[0036] In this embodiment, the laser light source 10 is a high beam quality 1064nm pulsed solid-state laser with fundamental mode output, ensuring that the laser beam has excellent monochromaticity and directionality, and providing a stable and reliable light source foundation for the debugging process.

[0037] The laser source device 10 has a single-pulse energy of 10mJ, providing sufficient energy density to ensure that the laser beam can maintain sufficient intensity after beam expansion, meeting the needs of debugging and testing.

[0038] The laser light source emitted by the laser light source 10 has a standard laser spot diameter of 1mm, ensuring that the initial size of the laser beam matches the entrance pupil size of the subsequent beam expander lens, thereby improving the accuracy and efficiency of debugging.

[0039] The standard laser beam expander 20 has a beam expansion factor of 3 to 8, which can cover the needs of most laser measuring instruments, while ensuring that the laser beam can be strictly controlled within the specified beam divergence angle range after beam expansion. The standard laser beam expander 20 is designed with a wavelength of 1064 nm, which is consistent with the output wavelength of the laser source device 10, ensuring that the laser beam does not undergo dispersion during transmission and maintains excellent wavefront performance.

[0040] The distance between the laser source 10 and the pinhole aperture 30 is not less than 3m, ensuring that the laser beam has enough space to expand freely and stabilize during transmission, reducing laser beam distortion and wavefront error caused by excessively short transmission distance, and improving the accuracy and reliability of debugging.

[0041] Further, please refer to Figure 2 and Figure 3 The laser beam expander lens 40 under test includes a lens barrel 41, an objective lens assembly 42, and an adjustable eyepiece assembly 43. These three parts together constitute the main structure of the beam expander lens, providing the necessary hardware foundation for laser beam expansion and wavefront optimization. The adjustable eyepiece assembly 43 is mounted on one end of the lens barrel 41 near the pinhole aperture 30 via an adjustable fastener 44, and the objective lens assembly 42 is mounted on the other end of the lens barrel 41. The design of the adjustable eyepiece assembly 43 allows for fine-tuning as needed to ensure that the laser beam maintains a stable transmission path and wavefront performance after passing through the eyepiece assembly, while also meeting the requirements for focal length adjustment.

[0042] The adjustable eyepiece assembly 43 includes an eyepiece mounting housing 431, an eyepiece element 432, and an adjustable washer 433. The coordinated action of these components allows the eyepiece assembly to precisely adjust its focus to meet the needs of different application scenarios. A mounting groove 411 is provided at the end of the lens barrel 41 furthest from the objective lens assembly 42. The eyepiece mounting housing 431 is placed in the mounting groove 411, which provides positioning and support for the installation of the eyepiece mounting housing 431, ensuring the stability and reliability of the adjustable eyepiece assembly 43 while maintaining sufficient flexibility for fine-tuning. A mounting cavity 434 is provided on the side of the eyepiece mounting housing 431 near the pinhole diaphragm 30. The eyepiece element 432 is installed within the mounting cavity 434. The mounting cavity 434 provides space for the installation of the eyepiece element 432, ensuring that the eyepiece element 432 can be accurately placed in the predetermined position. A light-transmitting hole 435 is provided on the side of the mounting cavity 434 near the objective lens assembly 42. The light-transmitting hole 435 passes through the mounting groove 411 and communicates with the lens barrel 41, providing a necessary channel for the transmission of the laser beam. A mounting ring 436 protrudes from the end of the eyepiece mounting housing 431 away from the objective lens assembly 42. This mounting ring 436 provides positioning and support for the installation of the adjustable fastener 44, ensuring that the eyepiece assembly can be firmly fixed to the lens barrel 41. The mounting ring 436 has fastening mounting holes 437 that are adapted to the adjustable fastener 44, ensuring an adjustable and stable connection between the mounting ring 436 and the lens barrel 41. An adjustable washer 433 is fitted onto the eyepiece mounting housing 431 and located between the mounting ring 436 and the lens barrel 41, used for adjusting the focal length. By adjusting the thickness of the adjustable washer 433, the distance between the eyepiece 432 and the objective lens assembly 42 can be precisely changed, thereby achieving fine-tuning of the focus to meet the needs of different application scenarios.

[0043] Furthermore, the distance between the adjustable washer 433 and the pinhole aperture 30 is 5mm to 15mm. This design ensures that the adjustable washer 433 will not cause excessive interference to the transmission of the laser beam when adjusting the focus, while providing a sufficient adjustment range to meet the needs of different focus adjustments. The thickness of the adjustable washer 433 is 0.5mm to 1mm. This thickness range allows for more precise adjustment, enabling minute adjustments to the focus, thereby ensuring that the beam divergence angle and wavefront performance of the laser beam reach their optimal state.

[0044] In addition, the laser beam expander wavefront adjustment and testing device also includes:

[0045] An adjustable platform (not shown in the figure) is mounted on which the laser source 10 is installed. The adjustable platform (not shown in the figure) is used to adjust the emission direction of the laser source 10, ensuring that the laser beam can accurately point to the target position, thereby improving the accuracy and efficiency of debugging. Specifically, the adjustable platform (not shown in the figure) is used to adjust the laser azimuth and elevation until the laser is output horizontally in both directions.

[0046] An optical platform (not shown in the figure) is positioned beside the adjustable platform (not shown in the figure). The standard laser beam expander 20, pinhole aperture 30, the laser beam expander under test 40, and the shearing interferometer 50 are all sequentially and adjustablely mounted on the optical platform (not shown in the figure). The optical platform (not shown in the figure) provides a stable and reliable foundation for the entire debugging and testing device, while ensuring the accuracy of the relative positions and angles between the various components. Through adjustable mounting, each component can be fine-tuned according to actual needs, thereby achieving precise control over the laser beam transmission path and wavefront performance.

[0047] The specific debugging steps are as follows:

[0048] S01: Azimuth and elevation of the calibration standard laser source.

[0049] The laser light source 10 is fixed on an adjustable platform (not shown in the figure) with adjustable azimuth and pitch. Small apertures 30 of the same height are set near the light outlet of the laser light source 10 and at a distance of not less than 3m. By adjusting the azimuth and pitch angle of the laser light source 10, the laser beam can be output horizontally in both directions.

[0050] S02: Azimuth and elevation calibration and wavefront detection of standard laser beam expander 20.

[0051] A standard laser beam expander 20 is placed behind the laser source 10, and its height, azimuth, and pitch angle are adjusted to ensure that the laser beam enters the standard laser beam expander 20 normally. Then, the laser beam is introduced into the shearing interferometer 50. By fine-tuning the azimuth and pitch of the standard laser beam expander 20, the interference fringes observed on the shearing interferometer 50 become straight fringes without tilt. This indicates that the wavefront quality of the laser beam after passing through the standard laser beam expander 20 is good. The interference fringe characteristics corresponding to this wavefront, such as shape, thickness, and tilt, are used as a reference for the subsequent adjustment of the laser beam expander 40 under test.

[0052] S03: Place the small aperture stop 30.

[0053] A pinhole aperture 30 is set behind the standard laser beam expander 20, and the aperture 435 of the pinhole aperture 30 is rotated to match the entrance pupil size of the laser beam expander 40 under test.

[0054] This step ensures that the diameter of the light spot incident on the laser beam expander 40 under test is consistent with the entrance pupil size of the laser beam expander 40 under test.

[0055] S04: Focusing test of the laser beam expander lens 40 under test.

[0056] First, place the adjustable washer 433 according to the preset theoretical value, and calibrate the laser beam expander 40 under test to ensure it is not off-center using a centering instrument or a center deviation measuring instrument.

[0057] Subsequently, the laser beam expander 40 to be tested is placed 5mm to 15mm behind the pinhole aperture 30 and mounted on the adjustment frame of the optical platform (not shown in the figure) for adjustment of height, azimuth and pitch angles, and then the adjustment frame on the optical platform is fixed.

[0058] Here, the tilt of the interference fringes on the shearing interferometer 50 is used to determine whether the laser beam expander lens 40 under test is out of focus. The thickness of the adjustable washer 433 is adjusted until the interference fringes are consistent with the interference fringes in step S02, thus completing the focusing.

[0059] It should be noted here that you should refer to [link / reference]. Figure 3 The laser beam expander lens 40 under test is designed based on the Galilean telescope principle, and its adjustable washer 433 is made of stainless steel by laser cutting.

[0060] S05: Installation stress adjustment and testing of the laser beam expander lens 40 under test.

[0061] After focusing, observe whether the interference fringes are straight. If there is a significant bend or asymmetry compared to the interference fringes in step S02, it may be due to lens eccentricity or installation stress. In this case, release the stress by fine-tuning the adjustable fastener 44 until the interference fringes return to straightness and are consistent with those in step S02, thus completing the stress adjustment.

[0062] S06: The laser beam expander lens 40 under test is debugged and tested in the laser measuring instrument.

[0063] After completing steps S01 to S05 of the debugging process, the wavefront of the laser beam expander lens 40 under test has been calibrated, and theoretically, the beam expansion factor is close to the design value. However, considering the influence of the laser beam incident direction on the wavefront, further testing is required within the entire laser measuring device. Please refer to [link / reference]. Figure 4 In the laser measuring device, a set of wedge mirrors 60 is placed behind the laser output window 70 to fine-tune the laser output direction, ensuring that the laser is incident directly on the laser beam expander lens 40 under test. By rotating the wedge mirrors 60, the curvature and tilt of the interference fringes are adjusted to match the reference in step S05. This indicates that the wavefront of the laser beam expander lens 40 under test has been well calibrated in the laser measuring device, and the beam expansion factor is close to the theoretical design value.

[0064] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A wavefront adjustment and testing device for a laser beam expander lens, used for adjusting and testing a laser beam expander lens (40) under test, characterized in that: The system includes a laser source (10) at the same height and coaxial, a standard laser beam expander (20), a pinhole aperture (30), and a shearing interferometer (50). The laser source (10) emits a standard laser source as a testing and debugging device. The standard laser beam expander (20) is located at the emitting end of the laser source (10) and is used to expand the standard laser source beam to an entrance pupil size that matches the laser beam expander (40) under test. The pinhole aperture (30) is located on the output optical path of the standard laser beam expander (20) and is used to... The spot diameter of the standard laser source entering the laser beam expander (40) under test is limited, and the spot diameter of the standard laser source entering the laser beam expander (40) under test is matched with the entrance pupil size of the laser beam expander (40) under test. The laser beam expander (40) under test is set at the light-emitting end of the aperture stop (30), and the shearing interferometer (50) is set in the output optical path of the laser beam expander (40) under test for testing the wavefront of the standard laser source after passing through the laser beam expander (40) under test.

2. The laser beam expander wavefront adjustment and detection device according to claim 1, characterized in that: The laser source device (10) is a high beam quality 1064nm pulsed solid-state laser with fundamental mode output.

3. The laser beam expander wavefront adjustment and detection device according to claim 1, characterized in that: The single-pulse energy of the laser light source (10) is 10mJ.

4. The laser beam expander wavefront adjustment and detection device according to claim 1, characterized in that: The laser spot diameter emitted by the laser light source (10) is 1 mm.

5. The laser beam expander wavefront adjustment and detection device according to claim 1, characterized in that: The beam expansion factor of the standard laser beam expander (20) is 3 to 8, and the design wavelength of the standard laser beam expander (20) is 1064 nm.

6. The laser beam expander wavefront adjustment and detection device according to claim 1, characterized in that: The distance between the laser light source (10) and the pinhole aperture (30) is not less than 3m.

7. The laser beam expander wavefront adjustment and detection device according to claim 1, characterized in that: The laser beam expander (40) under test includes a lens barrel (41), an objective lens assembly (42), and an adjustable eyepiece assembly (43). The adjustable eyepiece assembly (43) is mounted on one end of the lens barrel (41) near the pinhole aperture (30) by an adjustable fastener (44), and the objective lens assembly (42) is mounted on the other end of the lens barrel (41).

8. The laser beam expander wavefront adjustment and detection device according to claim 7, characterized in that: The adjustable eyepiece assembly (43) includes an eyepiece mounting housing (431), an eyepiece element (432), and an adjustable washer (433). A mounting groove (411) is provided at the end of the lens barrel (41) away from the objective lens assembly (42). The eyepiece mounting housing (431) is placed in the mounting groove (411). A mounting cavity (434) is provided on the side of the eyepiece mounting housing (431) near the pinhole aperture (30). The eyepiece element (432) is installed in the mounting cavity (434). The mounting cavity (434) is located near the objective lens assembly (432). 2) A light-transmitting hole (435) is provided on one side. The light-transmitting hole (435) passes through the mounting groove (411) and communicates with the lens barrel (41). The end of the eyepiece mounting housing (431) away from the objective lens assembly (42) is provided with a mounting protrusion ring (436). The mounting protrusion ring (436) is provided with a fastening mounting hole (437) that is adapted to the adjustable fastener (44). The adjustable washer (433) is sleeved on the eyepiece mounting housing (431) and is located between the mounting protrusion ring (436) and the lens barrel (41) for adjusting the focal length.

9. The laser beam expander wavefront adjustment and detection device according to claim 8, characterized in that: The distance between the adjustable washer (433) and the pinhole aperture (30) is 5mm to 15mm, and the thickness of the adjustable washer (433) is 0.5mm to 1mm.

10. The laser beam expander wavefront adjustment and detection device according to claim 1, characterized in that, Also includes: An adjustable platform is provided, wherein the laser source element (10) is mounted on the adjustable platform, and the adjustable platform is used to adjust the emission direction of the laser source element (10); An optical platform is set on the side of the adjustable platform, and the standard laser beam expander (20), pinhole aperture (30), laser beam expander under test (40), and shearing interferometer (50) are all sequentially and adjustablely mounted on the optical platform.

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