Device, method and equipment for detecting deviation of directional angle of double-frequency laser beam and medium

Abstract

The invention provides a dual-frequency laser beam directional angle deviation detection device and method, equipment and a medium. The device comprises a carrier interference light path and a directional angle deviation detection module. The carrier interference light path comprises a 1 / 4 wave plate, a birefringent prism, a polaroid, a light beam expanding module and a charge-coupled device; shielding the second laser beam or the first laser beam to enable the first laser beam or the second laser beam to sequentially pass through a 1 / 4 wave plate, a birefringent prism, a polaroid, a beam expanding module and a charge-coupled device to obtain a first interference fringe pattern corresponding to the first laser beam or a second interference fringe pattern corresponding to the second laser beam; and the directional angle deviation detection module is used for analyzing and detecting the directional angle deviation between the first laser beam and the second laser beam through the interference fringe pattern. According to the device, when the directional angle deviation is very small and is as small as milliradian or even microradian level, the accurate detection of the directional angle deviation of the light beam can be realized.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and more specifically, to a device, method, equipment, and medium for detecting the pointing angle deviation of a dual-frequency laser beam. Background Technology

[0002] Dual-frequency laser interferometers combine high resolution and strong anti-interference capabilities in ultra-precision measurements, with their speed limit directly determined by the frequency difference between the two lasers. To overcome the bottleneck of frequency difference of only a few megahertz in the traditional Zeeman effect, an acousto-optic frequency shifter is used to shift the frequencies of the two laser beams separately before spatially combining them, achieving a frequency difference of tens to hundreds of megahertz, thus meeting the requirements of high-speed dynamic measurement.

[0003] However, the method of achieving large frequency difference through frequency shifting and beam combining requires extremely precise control over the pointing angle deviation of the two laser beams after combining. In practical engineering applications, this pointing angle is prone to deviation. This deviation directly manifests as an angular shift between the reference beam and the measurement beam, thereby altering the signal strength. Its impact is particularly significant in multi-degree-of-freedom measurement scenarios. Therefore, detecting the pointing angle deviation of the dual-frequency laser beams is a crucial factor in ensuring the measurement performance of large frequency difference multi-degree-of-freedom laser interferometers.

[0004] Common methods for detecting beam pointing angle deviation mainly rely on geometric optics methods (such as collimator method and geometric calibration method), but their measurement resolution is limited by factors such as camera pixel size and measurement distance. When the pointing angle deviation we want to measure is very small, down to the milliradian level or even the microradian level, the requirements for testing conditions, hardware performance, and algorithm processing are extremely high, making them difficult to achieve in practical applications. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a device, method, equipment and medium for detecting the pointing angle deviation of a dual-frequency laser beam, which can achieve accurate detection of the pointing angle deviation when the pointing angle deviation is very small, down to the milliradian level or even the microradian level.

[0006] In a first aspect, embodiments of this application provide a device for detecting the pointing angle deviation of a dual-frequency laser beam. The device includes: a carrier interference optical path and a pointing angle deviation detection module; the carrier interference optical path includes a quarter-wave plate, a birefringent prism, a polarizer, a beam expander module, and a charge-coupled device. The first laser beam or the second laser beam is blocked. The first laser beam or the second laser beam passes sequentially through the quarter-wave plate, the birefringent prism, the polarizer, the beam expander module, and the charge-coupled device to obtain the first interference fringe pattern corresponding to the first laser beam or the second interference fringe pattern corresponding to the second laser beam. The first laser beam or the second laser beam is obtained by frequency shifting and spatially combining two laser beams emitted by a dual-frequency laser through an acousto-optic frequency shifter. The pointing angle deviation detection module is used to detect the pointing angle deviation between the first laser beam and the second laser beam based on the first interference fringe pattern and the second interference fringe pattern.

[0007] In one possible implementation, any laser beam sequentially passes through the quarter-wave plate, the birefringent prism, the polarizer, the beam expander, and the charge-coupled device to obtain a corresponding interference fringe pattern, including: The laser beam passes through the quarter-wave plate to obtain circularly polarized light; The circularly polarized light is decomposed into two beams of light with orthogonal polarization by the birefringent prism. The two beams of light with orthogonal polarization pass through the polarizer to form two beams with the same transmission direction; The two beams with the same transmission direction are expanded by the beam expanding module and then projected onto the target surface of the charge-coupled device, where they interfere and form an interference fringe pattern corresponding to the laser beam.

[0008] In one possible implementation, the beam expanding module includes a first lens and a second lens; beams with the same transmission direction are expanded by the beam expanding module, including: The laser beam is expanded by passing through the first lens and the second lens in sequence.

[0009] In one possible implementation, the pointing angle deviation detection module includes a calculation unit and a determination unit; The calculation unit is used to calculate the angle difference between the interference angle corresponding to the first interference fringe pattern and the interference angle corresponding to the second interference fringe pattern based on the fringe spacing corresponding to the first interference fringe pattern and the fringe spacing corresponding to the second interference fringe pattern. The determining unit is used to determine the angle difference as the pointing angle deviation between the first laser beam and the second laser beam.

[0010] In one possible implementation, the computing unit is specifically used for: Substituting the fringe spacing corresponding to the first interference fringe pattern and the fringe spacing corresponding to the second interference fringe pattern into the following formula, we obtain the angle difference between the interference angle corresponding to the first interference fringe pattern and the interference angle corresponding to the second interference fringe pattern: ; ; ; in, The angle between the two beams obtained after the first laser beam passes sequentially through the quarter-wave plate and the birefringent prism is denoted by . The wavelength of the first laser beam is... The fringe spacing corresponds to the first interference fringe pattern. The angle between the two beams obtained after the second laser beam passes sequentially through the quarter-wave plate and the birefringent prism is denoted by . The wavelength of the second laser beam is . The fringe spacing corresponding to the second interference fringe pattern. The angle difference between the interference angle corresponding to the first interference fringe pattern and the interference angle corresponding to the second interference fringe pattern.

[0011] In one possible implementation, the computing unit is further configured to determine the fringe spacing corresponding to any interference fringe pattern according to the following steps: Any line in the interference fringe pattern that is perpendicular to the fringe direction is designated as an index line; Using the position of the target pixel on the index line as the horizontal axis and the pixel value of the target pixel as the vertical axis, a pixel intensity distribution curve of the index interference fringes is plotted; the target pixel is the pixel on the index line. The horizontal distance between adjacent peaks on the pixel intensity distribution curve of the indexed interference fringes is determined as the fringe spacing corresponding to the interference fringe pattern.

[0012] Secondly, embodiments of this application also provide a method for detecting the pointing angle deviation of a dual-frequency laser beam. This method is applied to the pointing angle deviation detection module in the dual-frequency laser beam pointing angle deviation detection device as described in any of the first aspects, wherein the detection device further includes a carrier interference optical path; the method includes: Based on the first and second interference fringe patterns, the pointing angle deviation between the first and second laser beams is detected; the first or second laser beam is obtained by spatially combining two laser beams emitted by a dual-frequency laser interferometer after frequency shifting by an acousto-optic frequency shifter. The first interference fringe pattern and the second interference fringe pattern are obtained by blocking the second laser beam or the first laser beam emitted by the dual-frequency laser interferometer. The first laser beam or the second laser beam passes sequentially through the quarter-wave plate, birefringent prism, polarizer, beam expander module and charge coupling device in the carrier interference optical path to obtain the first interference fringe pattern corresponding to the first laser beam or the second interference fringe pattern corresponding to the second laser beam.

[0013] In one possible implementation, detecting the pointing angle deviation between the first laser beam and the second laser beam based on the first interference fringe pattern and the second interference fringe pattern includes: Based on the fringe spacing corresponding to the first interference fringe pattern and the fringe spacing corresponding to the second interference fringe pattern, calculate the angle difference between the interference angle corresponding to the first interference fringe pattern and the interference angle corresponding to the second interference fringe pattern. The angle difference is defined as the pointing angle deviation between the first laser beam and the second laser beam.

[0014] In one possible implementation, calculating the angle difference between the interference angles corresponding to the first interference fringe pattern and the second interference fringe pattern based on the fringe spacing corresponding to the first interference fringe pattern and the fringe spacing corresponding to the second interference fringe pattern includes: Substituting the fringe spacing corresponding to the first interference fringe pattern and the fringe spacing corresponding to the second interference fringe pattern into the following formula, we obtain the angle difference between the interference angle corresponding to the first interference fringe pattern and the interference angle corresponding to the second interference fringe pattern: ; ; ; in, The angle between the two beams obtained after the first laser beam passes sequentially through the quarter-wave plate and the birefringent prism is denoted by . The wavelength of the first laser beam is... The fringe spacing corresponds to the first interference fringe pattern. The angle between the two beams obtained after the second laser beam passes sequentially through the quarter-wave plate and the birefringent prism is denoted by . The wavelength of the second laser beam is . The fringe spacing corresponding to the second interference fringe pattern. The angle difference between the interference angle corresponding to the first interference fringe pattern and the interference angle corresponding to the second interference fringe pattern.

[0015] In one possible implementation, the fringe spacing corresponding to any interference fringe pattern is determined according to the following steps: Any line in the interference fringe pattern that is perpendicular to the fringe direction is designated as an index line; Using the position of the target pixel on the index line as the horizontal axis and the pixel value of the target pixel as the vertical axis, a pixel intensity distribution curve of the index interference fringes is plotted; the target pixel is the pixel on the index line. The horizontal distance between adjacent peaks on the pixel intensity distribution curve of the indexed interference fringes is determined as the fringe spacing corresponding to the interference fringe pattern.

[0016] Thirdly, embodiments of this application also provide an electronic device, including: a processor, a storage medium, and a bus, wherein the storage medium stores machine-readable instructions executable by the processor, and when the electronic device is running, the processor communicates with the storage medium via the bus, and the processor executes the machine-readable instructions to perform the steps of the dual-frequency laser beam pointing angle deviation detection method as described in any of the second aspects.

[0017] Fourthly, embodiments of this application also provide a computer-readable storage medium storing a computer program, which, when executed by a processor, performs the steps of the method for detecting the pointing angle deviation of a dual-frequency laser beam as described in any of the second aspects.

[0018] This application provides a device, method, equipment, and medium for detecting the pointing angle deviation of a dual-frequency laser beam. The device includes a carrier interference optical path and a pointing angle deviation detection module. The carrier interference optical path includes a quarter-wave plate, a birefringent prism, a polarizer, a beam expander module, and a charge-coupled device (CCD). The first or second laser beam is blocked, and the first or second laser beam sequentially passes through the quarter-wave plate, birefringent prism, polarizer, beam expander module, and CCD to obtain a first interference fringe pattern corresponding to the first laser beam or a second interference fringe pattern corresponding to the second laser beam. The pointing angle deviation detection module is used to detect the pointing angle deviation between the first and second laser beams based on the first and second interference fringe patterns. This device enables accurate detection of beam pointing angle deviation even when the deviation is very small, down to the milliradian or even microradian level. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This paper shows a schematic diagram of the structure of a dual-frequency laser beam pointing angle deviation detection device provided in an embodiment of this application; Figure 2 This document illustrates a flowchart of an embodiment of the present application for acquiring interference fringe patterns based on a carrier interference optical path. Figure 3 A schematic diagram of the beam interference pattern at the original magnification provided in an embodiment of this application is shown; Figure 4 A schematic diagram of the beam interference pattern obtained after passing through the first lens and the second lens according to an embodiment of this application is shown; Figure 5 A schematic diagram of the pixel intensity distribution curve of the indexed interference fringes provided in an embodiment of this application is shown; Figure 6 A schematic diagram of the structure of an electronic device provided in an embodiment of this application is shown. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the accompanying drawings in this application are for illustrative and descriptive purposes only and are not intended to limit the scope of protection of this application. Furthermore, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this application illustrate operations implemented according to some embodiments of this application. It should be understood that the operations in the flowcharts may not be implemented in sequence, and steps without logical contextual relationships may be reversed or implemented simultaneously. In addition, those skilled in the art, guided by the content of this application, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts.

[0022] Furthermore, the described embodiments are merely some, not all, of the embodiments of this application. The components of the embodiments of this application described and illustrated herein can typically be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0023] To enable those skilled in the art to utilize the content of this application, and in conjunction with the specific application scenario of "laser technology," the following embodiments are provided. For those skilled in the art, the general principles defined herein can be applied to other embodiments and application scenarios without departing from the spirit and scope of this application. Although this application is primarily described within the "laser technology field," it should be understood that this is merely an exemplary embodiment.

[0024] It should be noted that the term "comprising" will be used in the embodiments of this application to indicate the presence of the features declared thereafter, but does not exclude the addition of other features.

[0025] Reference Figure 1 The diagram shows a schematic of a dual-frequency laser beam pointing angle deviation detection device provided in an embodiment of this application. The device includes a carrier interference optical path 101 and a pointing angle deviation detection module 102. The carrier interference optical path 101 includes a quarter-wave plate, a birefringent prism (such as a Rochon prism), a polarizer, a beam expander module, and a charge-coupled device (CCD). The beam expander module includes a first lens and a second lens.

[0026] The dual-frequency laser interferometer emits two laser beams with different frequencies. These two lasers are frequency-shifted by an acousto-optic frequency shifter and then spatially combined to obtain a first laser beam and a second laser beam. The polarization states of the first and second laser beams are orthogonal. The polarization direction of the quarter-wave plate is perpendicular to the polarization direction of the laser beam emitted by the dual-frequency laser interferometer. Placement. The polarizer is perpendicular to the polarization direction of the laser beam emitted by the dual-frequency laser interferometer. Placement. A quarter-wave plate is a thin sheet of birefringent crystal whose thickness is precisely machined so that the phase difference between the o-ray and e-ray is exactly π / 2 or an odd multiple thereof.

[0027] The first laser beam or the second laser beam is blocked. The first or second laser beam then passes sequentially through a quarter-wave plate, a birefringent prism, a polarizer, a beam expander, and a charge-coupled device, resulting in a first interference fringe pattern corresponding to the first laser beam or a second interference fringe pattern corresponding to the second laser beam. The first or second laser beam is obtained by spatially combining two laser beams emitted from a dual-frequency laser interferometer after frequency shifting by an acousto-optic frequency shifter. In the embodiments of this application, reference is made to Figure 2 The diagram shows a flowchart of an example of acquiring interference fringe patterns based on a carrier interference optical path according to an embodiment of this application. The second laser beam is blocked, and the first laser beam is passed sequentially through a quarter-wave plate, a birefringent prism, a polarizer, a beam expander module, and a charge-coupled device to obtain the first interference fringe pattern corresponding to the first laser beam. The first laser beam is then blocked, and the second laser beam is passed sequentially through a quarter-wave plate, a birefringent prism, a polarizer, a beam expander module, and a charge-coupled device to obtain the second interference fringe pattern of the second laser beam.

[0028] Alternatively, the first laser beam is blocked, and the second laser beam is passed sequentially through a quarter-wave plate, a birefringent prism, a polarizer, a beam expander module, and a charge-coupled device to obtain the second interference fringe pattern corresponding to the second laser beam; the second laser beam is blocked, and the first laser beam is passed sequentially through a quarter-wave plate, a birefringent prism, a polarizer, a beam expander module, and a charge-coupled device to obtain the first interference fringe pattern corresponding to the first laser beam.

[0029] Specifically, any laser beam sequentially passes through a quarter-wave plate, a birefringent prism, a polarizer, a beam expander, and a charge-coupled device (CCD) to obtain a corresponding interference fringe pattern. This process includes: the laser beam passes through a quarter-wave plate to obtain circularly polarized light; the circularly polarized light passes through a birefringent prism and is decomposed into two beams with orthogonal polarization; the two beams with orthogonal polarization pass through a polarizer to form two beams with the same transmission direction; the two beams with the same transmission direction are expanded by the beam expander and then projected onto the target surface of the CCCD, where they interfere to form an interference fringe pattern corresponding to the laser beam.

[0030] In this embodiment, two beams with the same transmission direction are expanded by a beam expanding module and then projected onto the target surface of a charge-coupled device (CCD). The interference fringes on the target surface are recorded by the CCD to form a pattern.

[0031] Furthermore, the beam expanding module includes a first lens and a second lens; any beam with the same transmission direction is expanded by the beam expanding module, including: the laser beam is expanded by passing through the first lens (lens-1) and the second lens (lens-2) in sequence.

[0032] Specifically, the second laser beam is blocked, and the first laser beam is passed sequentially through a quarter-wave plate, a birefringent prism, a polarizer, a first lens (lens-1), a second lens (lens-2), and a charge-coupled device (CCD) to obtain the first interference fringe pattern corresponding to the first laser beam; the first laser beam is blocked, and the second laser beam is passed sequentially through a quarter-wave plate, a birefringent prism, a polarizer, a first lens (lens-1), a second lens (lens-2), and a CCD to obtain the second interference fringe pattern of the second laser beam. Alternatively, the first laser beam is blocked, and the second laser beam is passed sequentially through a quarter-wave plate, a birefringent prism, a polarizer, a first lens (lens-1), a second lens (lens-2), and a CCD to obtain the second interference fringe pattern of the second laser beam; the second laser beam is blocked, and the first laser beam is passed sequentially through a quarter-wave plate, a birefringent prism, a polarizer, a first lens (lens-1), a second lens (lens-2), and a CCD to obtain the first interference fringe pattern corresponding to the first laser beam.

[0033] Here, compared with the existing two-beam angle measurement method based on geometric optics, the pointing angle detection of the present application embodiment has the following advantages: (1) The carrier interference of the beam can be realized by using the combination of a quarter-wave plate, a birefringent prism and a polarizer, and the angle measurement (i.e. the angle between the two beams obtained after the first laser beam passes through the quarter-wave plate and the birefringent prism in sequence) can be used to measure the angle between the two beams. ( Figure 2 In The angle between the two beams obtained after the second laser beam passes sequentially through the quarter-wave plate and the birefringent prism. ( Figure 2 In (2) Refer to the processing of interference fringes. Figure 3 The image shown is a schematic diagram of the beam interference pattern at the original magnification provided in an embodiment of this application; refer to... Figure 4 The image shown is a schematic diagram of the beam interference pattern obtained after passing through the first lens and the second lens according to an embodiment of this application. (Comparison) Figure 3 and Figure 4 It can be seen that by using a double lens (first lens and second lens to expand the beam) to magnify the interference fringes, the measurement resolution can be improved without changing the camera resolution. (3) The measurement process only requires blocking the beam to complete the acquisition of the interference fringe pattern. The optical path is stable and the external influence on the measurement is small. (4) This carrier measurement method effectively avoids the influence of low-frequency interference fringe noise and improves the measurement accuracy.

[0034] Example 1, with a Rochon prism separation angle of... The pixel size is 2000×2000 pixels, and the cell size is... The first laser beam is incident normally, the second laser beam makes an angle of 0.1° with the first laser beam, and the beam expander has a magnification of 100 times. The resulting beam will look like... Figure 4 The beam interference pattern shown.

[0035] The pointing angle deviation detection module 102 is used to detect the pointing angle deviation between the first laser beam and the second laser beam based on the first interference fringe pattern and the second interference fringe pattern. The pointing angle deviation detection module includes a calculation unit and a determination unit.

[0036] The calculation unit is used to calculate the angle difference between the interference angles corresponding to the first interference fringe pattern and the second interference fringe pattern based on the fringe spacing corresponding to the first interference fringe pattern and the fringe spacing corresponding to the second interference fringe pattern.

[0037] In this embodiment of the application, the calculation unit is specifically used to substitute the fringe spacing corresponding to the first interference fringe pattern and the fringe spacing corresponding to the second interference fringe pattern into the following formula to obtain the angle difference between the interference angle corresponding to the first interference fringe pattern and the interference angle corresponding to the second interference fringe pattern: ; ; ; in, The angle between the two beams obtained after the first laser beam passes through the quarter-wave plate and the birefringent prism in sequence (i.e., the interference angle corresponding to the first interference fringe pattern). The wavelength of the first laser beam is... The fringe spacing corresponds to the first interference fringe pattern. The angle between the two beams obtained after the second laser beam passes through the quarter-wave plate and the birefringent prism in sequence (i.e., the interference angle corresponding to the second interference fringe pattern). The wavelength of the second laser beam is . The fringe spacing corresponding to the second interference fringe pattern. The angle difference is the angle between the interference angle corresponding to the first interference fringe pattern and the interference angle corresponding to the second interference fringe pattern.

[0038] The calculations were based on Examples 1 and 2. Approximately , Approximately , Approximately .

[0039] The calculation unit is also used to determine the fringe spacing corresponding to any interference fringe pattern according to the following steps: Step 1: Determine any line perpendicular to the fringe direction in the interference fringe pattern as the index line; use the position of the target pixel on the index line as the x-axis and the pixel value of the target pixel as the y-axis to plot the pixel intensity distribution curve of the index interference fringes.

[0040] In the embodiments of this application, Figure 4 The dashed line perpendicular to the stripes is the index line. Based on Example 1, refer to... Figure 5 The diagram shown is a schematic representation of the pixel intensity distribution curve of the indexed interference fringes provided in an embodiment of this application. The pixel value of a pixel is its light intensity (light power density, or simply "brightness").

[0041] Step 2: The target pixel is the pixel on the index line; the horizontal distance between adjacent peaks on the pixel intensity distribution curve of the index interference fringes ( Figure 5 middle and The spacing between the fringes is determined to be the fringe spacing corresponding to the interference fringe pattern.

[0042] The determining unit is used to determine the angle difference as the pointing angle deviation between the first laser beam and the second laser beam.

[0043] In the embodiments of this application, the separation angle of the Rochon prism differs under different incident angles, indicating that the performance of the Rochon prism is sensitive to the incident angle. When the incident angle between the first laser beam and the second laser beam is very small (i.e., the directivity deviation is very small, as small as milliradians or even microradians), then approximately: ;in, This represents the angle difference between the first and second laser beams. Therefore, the angle difference... The deviation is determined to be the pointing angle difference between the first laser beam and the second laser beam.

[0044] Pointing angle deviation refers to the angle between two laser beams of different frequencies in a dual-frequency laser interferometer when they are combined in space due to manufacturing and integration errors in the combining device. This angle is typically on the order of microradians. When the angle is too large, it directly leads to an angle between the reference beam and the measurement beam of the laser interferometer, thereby reducing the contrast of the interference signal and affecting the measurement range of multiple degrees of freedom.

[0045] Based on the same inventive concept, this application also provides a method for detecting the pointing angle deviation of a dual-frequency laser beam, corresponding to the detection device for the pointing angle deviation of a dual-frequency laser beam. Since the principle of solving the problem by the method in this application is similar to the detection device for the pointing angle deviation of a dual-frequency laser beam described above in this application, the implementation of the method can refer to the implementation of the device, and the repeated parts will not be described again.

[0046] This application provides a flowchart of a method for detecting the pointing angle deviation of a dual-frequency laser beam. This method is applied to a pointing angle deviation detection module in a dual-frequency laser beam pointing angle deviation detection device, which further includes a carrier interference optical path. The method includes: detecting the pointing angle deviation between the first laser beam and the second laser beam based on a first interference fringe pattern and a second interference fringe pattern; the first laser beam or the second laser beam is obtained by frequency shifting and spatial beam combining of two laser beams emitted from a dual-frequency laser interferometer via an acousto-optic frequency shifter. The first interference fringe pattern and the second interference fringe pattern are obtained by blocking the second laser beam or the first laser beam emitted by the dual-frequency laser interferometer. The first laser beam or the second laser beam passes sequentially through the quarter-wave plate, birefringent prism, polarizer, beam expander module and charge coupling device in the carrier interference optical path to obtain the first interference fringe pattern corresponding to the first laser beam or the second interference fringe pattern corresponding to the second laser beam.

[0047] In one possible implementation, detecting the pointing angle deviation between the first laser beam and the second laser beam based on the first interference fringe pattern and the second interference fringe pattern includes: calculating the angle difference between the interference angle corresponding to the first interference fringe pattern and the interference angle corresponding to the second interference fringe pattern based on the fringe spacing corresponding to the first interference fringe pattern and the fringe spacing corresponding to the second interference fringe pattern; and determining the angle difference as the pointing angle deviation between the first laser beam and the second laser beam.

[0048] like Figure 6 As shown in the embodiment of this application, an electronic device 600 includes a processor 601, a memory 602, and a bus. The memory 602 stores machine-readable instructions that can be executed by the processor 601. When the electronic device is running, the processor 601 communicates with the memory 602 via the bus. The processor 601 executes the machine-readable instructions to perform the steps of the dual-frequency laser beam pointing angle deviation detection method described above.

[0049] Specifically, the memory 602 and processor 601 mentioned above can be general-purpose memory and processor, without any specific limitations. When the processor 601 runs the computer program stored in the memory 602, it can execute the above-mentioned method for detecting the pointing angle deviation of the dual-frequency laser beam.

[0050] Corresponding to the above-described method for detecting the pointing angle deviation of a dual-frequency laser beam, this application embodiment also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, performs the steps of the above-described method for detecting the pointing angle deviation of a dual-frequency laser beam.

[0051] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems and devices described above can be referred to the corresponding processes in the method embodiments, and will not be repeated here. In the several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed mutual coupling or direct coupling or communication connection can be through some communication interfaces; the indirect coupling or communication connection of devices or modules can be electrical, mechanical, or other forms.

[0052] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0053] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0054] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a processor-executable, non-volatile, computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0055] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A device for detecting the pointing angle deviation of a dual-frequency laser beam, characterized in that, The device includes: a carrier interference optical path and a pointing angle deviation detection module; the carrier interference optical path includes a quarter-wave plate, a birefringent prism, a polarizer, a beam expander module, and a charge-coupled device; The first laser beam or the second laser beam is blocked. The first laser beam or the second laser beam passes sequentially through the quarter-wave plate, the birefringent prism, the polarizer, the beam expander module, and the charge-coupled device to obtain the first interference fringe pattern corresponding to the first laser beam or the second interference fringe pattern corresponding to the second laser beam. The first laser beam or the second laser beam is obtained by frequency shifting and spatially combining two laser beams emitted by a dual-frequency laser through an acousto-optic frequency shifter. The pointing angle deviation detection module is used to detect the pointing angle deviation between the first laser beam and the second laser beam based on the first interference fringe pattern and the second interference fringe pattern.

2. The detection device for the pointing angle deviation of a dual-frequency laser beam according to claim 1, characterized in that, Any laser beam sequentially passes through the quarter-wave plate, the birefringent prism, the polarizer, the beam expander, and the charge-coupled device to obtain a corresponding interference fringe pattern, including: The laser beam passes through the quarter-wave plate to obtain circularly polarized light; The circularly polarized light is decomposed into two beams of light with orthogonal polarization by the birefringent prism. The two beams of light with orthogonal polarization pass through the polarizer to form two beams with the same transmission direction; The two beams with the same transmission direction are expanded by the beam expanding module and then projected onto the target surface of the charge-coupled device, where they interfere and form an interference fringe pattern corresponding to the laser beam.

3. The detection device for the pointing angle deviation of a dual-frequency laser beam according to claim 2, characterized in that, The beam expanding module includes a first lens and a second lens; beams with the same transmission direction are expanded by the beam expanding module, including: The laser beam is expanded by passing through the first lens and the second lens in sequence.

4. The detection device for the pointing angle deviation of a dual-frequency laser beam according to claim 2, characterized in that, The pointing angle deviation detection module includes a calculation unit and a determination unit; The calculation unit is used to calculate the angle difference between the interference angle corresponding to the first interference fringe pattern and the interference angle corresponding to the second interference fringe pattern based on the fringe spacing corresponding to the first interference fringe pattern and the fringe spacing corresponding to the second interference fringe pattern. The determining unit is used to determine the angle difference as the pointing angle deviation between the first laser beam and the second laser beam.

5. The detection device for the pointing angle deviation of a dual-frequency laser beam according to claim 4, characterized in that, The computing unit is specifically used for: Substituting the fringe spacing corresponding to the first interference fringe pattern and the fringe spacing corresponding to the second interference fringe pattern into the following formula, we obtain the angle difference between the interference angle corresponding to the first interference fringe pattern and the interference angle corresponding to the second interference fringe pattern: ； ； ； in, The angle between the two beams obtained after the first laser beam passes sequentially through the quarter-wave plate and the birefringent prism is denoted by . The wavelength of the first laser beam is... The fringe spacing corresponds to the first interference fringe pattern. The angle between the two beams obtained after the second laser beam passes sequentially through the quarter-wave plate and the birefringent prism is denoted by . The wavelength of the second laser beam is . The fringe spacing corresponding to the second interference fringe pattern. The angle difference between the interference angle corresponding to the first interference fringe pattern and the interference angle corresponding to the second interference fringe pattern.

6. The detection device for the pointing angle deviation of a dual-frequency laser beam according to claim 4, characterized in that, The calculation unit is also used to determine the fringe spacing corresponding to any interference fringe pattern according to the following steps: Any line in the interference fringe pattern that is perpendicular to the fringe direction is designated as an index line; Using the position of the target pixel on the index line as the horizontal axis and the pixel value of the target pixel as the vertical axis, a pixel intensity distribution curve of the index interference fringes is plotted; the target pixel is the pixel on the index line. The horizontal distance between adjacent peaks on the pixel intensity distribution curve of the indexed interference fringes is determined as the fringe spacing corresponding to the interference fringe pattern.

7. A method for detecting the pointing angle deviation of a dual-frequency laser beam, characterized in that, This method is applied to the pointing angle deviation detection module in the pointing angle deviation detection device for dual-frequency laser beams as described in any one of claims 1 to 6, wherein the detection device further includes a carrier interference optical path; the method includes: Based on the first and second interference fringe patterns, the pointing angle deviation between the first and second laser beams is detected; the first or second laser beam is obtained by spatially combining two laser beams emitted by a dual-frequency laser interferometer after frequency shifting by an acousto-optic frequency shifter. The first interference fringe pattern and the second interference fringe pattern are obtained by blocking the second laser beam or the first laser beam emitted by the dual-frequency laser interferometer. The first laser beam or the second laser beam passes sequentially through the quarter-wave plate, birefringent prism, polarizer, beam expander module and charge coupling device in the carrier interference optical path to obtain the first interference fringe pattern corresponding to the first laser beam or the second interference fringe pattern corresponding to the second laser beam.

8. The method for detecting the pointing angle deviation of a dual-frequency laser beam according to claim 7, characterized in that, The step of detecting the pointing angle deviation between the first laser beam and the second laser beam based on the first interference fringe pattern and the second interference fringe pattern includes: Based on the fringe spacing corresponding to the first interference fringe pattern and the fringe spacing corresponding to the second interference fringe pattern, calculate the angle difference between the interference angle corresponding to the first interference fringe pattern and the interference angle corresponding to the second interference fringe pattern. The angle difference is defined as the pointing angle deviation between the first laser beam and the second laser beam.

9. An electronic device, characterized in that, include: The device includes a processor, a storage medium, and a bus, wherein the storage medium stores machine-readable instructions executable by the processor, and when the electronic device is running, the processor communicates with the storage medium via the bus, and the processor executes the machine-readable instructions to perform the steps of the method for detecting the pointing angle deviation of a dual-frequency laser beam as described in any one of claims 7 and 8.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, performs the steps of the method for detecting the pointing angle deviation of a dual-frequency laser beam as described in claim 7 or 8.

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