A method for assembling and adjusting a Doppler asymmetric spatial heterodyne interferometer

Abstract

A method for assembling and adjusting a Doppler asymmetric spatial heterodyne interferometer belongs to the field of interference spectroscopy technology. To address the problem of relatively large overall assembly errors in existing Doppler asymmetric spatial heterodyne interferometers, the method includes parallel assembly and calibration of the front lens, rear lens, and collimating lens, using a centering instrument to detect the lens assembly and adjustment status, and using a reference reflector to align the folding mirror. After completion, the entire system is assembled and calibrated on a load mounting plate with the folding mirror assembly, beam splitter, filter, interference module, and camera. The folding mirror assembly is fine-tuned to ensure that the signal light enters the optical path in a collimated manner. The collimating lens reflector is then adjusted to ensure that the calibration light enters the optical path in parallel. The camera position is then adjusted to obtain clear imaging. Using a system-integrated assembly and calibration method, the front lens, rear lens, and collimating lens can be assembled and calibrated in parallel, improving assembly and adjustment efficiency. After completion, the entire system is assembled and calibrated with the remaining components. The integrated optical path design ensures that the optical axes of each component are not deviated, reducing the impact of assembly errors and thus obtaining high-quality interference fringes.

Description

Technical Field

[0001] The invention belongs to the technical field of interference spectroscopy, and in particular relates to an assembling and adjusting method of a Doppler asymmetric spatial heterodyne interferometer. Background Art

[0002] Atmospheric winds play a crucial role in atmospheric dynamics and energetics. Neutral winds in the thermosphere influence the interactions between neutral molecules and plasma, and are relevant to space weather forecasting and modern satellite communications. Passive wind field detection techniques, which observe the Doppler shift of the natural atmospheric radiation spectrum, reveal airglow lines emitted by oxygen atoms and molecules in the middle and upper atmosphere. The Doppler shifts of these lines can be used as targets for measuring thermospheric neutral winds. Currently, traditional optical interferometers, such as wide-angle Michelson interferometers and Fabry-Lobert interferometers, are widely used for detecting neutral winds in the middle and upper atmosphere. However, these instruments are significantly affected by mechanical control and processing. Therefore, new interferometric spectroscopy techniques are needed. The Doppler asymmetric spatial heterodyne interferometer, a Michelson interferometer developed based on the principles of spatial heterodyne spectroscopy interferometry, offers a large field of view, ultra-high resolution, high throughput, no moving mirrors, simple manufacturing, and a lightweight and compact size.

[0003] The Doppler asymmetric spatial heterodyne interferometer can detect multiple spectral lines at the same time. The atmospheric airglow enters the system from the front mirror group, and after being split by the beam splitter prism, a phase difference is generated by the field widening prism. The airglow is incident on the blazed grating and diffracted back. The propagation direction of the two returning wavefronts has a small angle with the optical axis, forming spatial interference fringes. The interference fringes containing height profile information can be detected at one time by the array detector, and the atmospheric wind field information can be finally obtained through phase inversion.

[0004] In the process of obtaining atmospheric wind field information, interferometers play a vital role. To obtain clear and neat interference fringes, it is necessary to strictly control the installation and adjustment of the interferometer and design the installation and adjustment workpiece to reduce the subsequent impact on the inverted wind speed error.

[0005] The Chinese patent publication number is "CN 107238438 A," and the patent name is "Assembly and Adjustment Method for Doppler Differential Interferometer." The method mainly includes steps such as establishing a system reference, adjusting the beam splitter prism, adjusting the field-of-view widening prism, and adjusting the grating. However, this technology only controls the precision of individual components of the interferometer, and the overall adjustment error is relatively large. Using traditional adjustment methods will have a significant impact on the quality of the interference pattern. Summary of the Invention

[0006] In order to solve the problem of large overall adjustment error of the existing Doppler asymmetric spatial heterodyne interferometer, a Doppler asymmetric spatial heterodyne interferometer adjustment method is proposed. The method has a simple structure and is easy to implement, and can be used for precise adjustment of the Doppler asymmetric spatial heterodyne interferometer.

[0007] The technical solution of the present invention is:

[0008] A method for assembling and adjusting a Doppler asymmetric spatial heterodyne interferometer comprises the following steps:

[0009] Step 1: Establish the installation benchmark;

[0010] Place theodolite 1 and theodolite 2 on a horizontal platform, adjust the level of the two theodolites and establish a reference. Use the light emitted by the calibrated autocollimator of theodolite 1 to establish a horizontal reference. The state must not be changed after the reference is established.

[0011] Step 2, install and adjust the front lens;

[0012] Place the first and second lens tubes on the azimuth and elevation adjustment platform, attach the reference reflector 1 to the light inlet flange of the first lens tube, make the collimator emit light, and adjust the azimuth and elevation platform so that the light returned by the reference reflector enters the center of the field of view of the autocollimator to establish the reference state.

[0013] Adjust lens group 1 to lens barrel 1, lens group 2, and lens group 3 to lens barrel 2 respectively, and use a centering instrument to detect the position of the lens spherical center image for correction;

[0014] Using the reference established by the self-collimating collimator and the lens barrel, install the folding mirror 1 on the lens barrel, and adjust the angle of the folding mirror 1 so that the light emitted by the collimator is focused to the center of the star point plate through the folding mirror 1.

[0015] Using the reference established by the self-collimating collimator and the second lens barrel, install the second folding mirror on the second lens barrel and adjust the angle of the second folding mirror so that the light emitted by the collimator is focused to the center of the star point plate through the second folding mirror.

[0016] Fix the lens barrel 1 and the lens barrel 2 through the flange to realize the integrated assembly and calibration of the front lens;

[0017] Step 3, install and adjust the rear lens;

[0018] Adjust lens group 4 to lens barrel 3, lens group 5, lens group 6 to lens barrel 4 respectively, use a centering instrument to check the position of the lens spherical center image and make corrections, fix lens barrel 3 and lens barrel 4 with flanges to keep the optical axis concentric;

[0019] Place lens barrels 3 and 4 on the azimuth and elevation adjustment platforms, place theodolite 1 in front of the mounting flange of lens barrel 3, and theodolite 2 in front of the mounting flange of lens barrel 4. Attach reference reflectors 1 and 2 to the surfaces of the mounting flanges of lens barrels 3 and 4. Use theodolite 1 to align reference reflector 1, and adjust theodolite 1 so that its optical axis is perpendicular to the mounting flange of lens barrel 3. Use theodolite 2 to align reference reflector 2, and adjust theodolite 2 so that its optical axis is perpendicular to the mounting flange of lens barrel 4 to establish the reference state.

[0020] Using the datum established by the theodolite and lens tubes three and four, install folding mirror three, adjust the angle of the folding mirror so that the crosshairs of the target emitted by theodolite one are imaged in the field of view of theodolite two, and move it to the center of the field of view;

[0021] Step 4, assemble the overall components;

[0022] Place the load mounting plate on the azimuth-pitch adjustment table, attach a reference reflector 1 to the reference surface of the load mounting plate, make the collimator emit light, and adjust the azimuth-pitch table so that the light returned by the reference reflector enters the center of the field of view of the autocollimator to establish the reference state;

[0023] Using the reference established by the load mounting plate and the autocollimator, install the folding mirror assembly onto the load mounting plate. Adjust the angle of the folding mirror assembly so that the light emitted by the collimator is reflected back to the center of the autocollimator's field of view through the front lens filter.

[0024] Install the collimator and the collimator lens reflector on the payload mounting plate, and install the camera on the payload mounting plate. Make the collimator emit light, and image it on the camera through the front lens, interferometer module, and rear lens. Adjust the collimator lens reflector to move the imaging light spot to the center of the camera's field of view. Adjust the camera defocus to make the imaging light spot the clearest image in the field of view.

[0025] After fixing all components, the Doppler asymmetric spatial heterodyne interferometer is assembled and adjusted.

[0026] In step 2, adjust the front lens, use a centering instrument to check the lens assembly, and then apply glue to fix the lens assembly.

[0027] In step 2, adjust the front lens, match and fix the star point plate to the lens barrel outlet, and make their optical axes concentric.

[0028] During the overall assembly in step 4, the front lens, rear lens, and collimator lens can be assembled and adjusted in parallel. After the assembly is completed, the remaining components can be assembled.

[0029] The beneficial effects of the present invention are as follows: the present invention adopts a system integration assembly and adjustment method to improve the overall assembly and adjustment accuracy, wherein the front lens, rear lens, and collimating lens three parts can be assembled and calibrated in parallel, thereby improving the assembly and adjustment efficiency. After completion, the whole machine is assembled and calibrated with the remaining parts, reducing the influence of installation errors and thus obtaining high-quality interference fringes. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the Doppler asymmetric spatial heterodyne interferometer after installation and adjustment;

[0031] Among them, 1-folding mirror assembly; 2-beam splitter prism; 3-collimating lens reflector; 4-filter; 5-collimating mirror; 6-front lens; 7-load mounting plate; 8-interference module; 9-rear lens; 10-imaging camera.

[0032] Figure 2 It is the front lens of Doppler asymmetric spatial heterodyne interferometer;

[0033] Among them, 6-1-lens group 1; 6-2-lens barrel 1; 6-3-folding mirror 1; 6-4-lens group 2; 6-5-folding mirror 2; 6-6-lens group 3; 6-7-lens barrel 2;

[0034] Figure 3 It is the rear lens of Doppler asymmetric spatial heterodyne interferometer;

[0035] Among them, 9-1-lens group four; 9-2-lens barrel three; 9-3-lens group five; 9-4-lens barrel four; 9-5-folding lens three; 9-6-lens group six.

[0036] Figure 4 The figure is a flow chart of the installation and adjustment method of the Doppler asymmetric spatial heterodyne interferometer. DETAILED DESCRIPTION

[0037] The present invention will be further described and illustrated below in conjunction with the accompanying drawings.

[0038] like Figure 1 As shown, a Doppler asymmetric spatial heterodyne interferometer system includes a folding mirror assembly 1, a beam splitter prism 2, a collimating lens reflector 3, a filter 4, a collimating lens 5, a front lens 6, a load mounting plate 7, an interference module 8, a rear lens 9, and an imaging camera 10. The components are integrated with the load mounting plate 7 through flanges; the signal light enters the system from the incident port of the folding mirror assembly 1, is deflected 90 degrees by the folding mirror assembly 1, and then emitted; the emitted light enters the beam splitter prism 2 and is then filtered by the filter 4, and the filtered light is then filtered. The rear signal light is collimated and folded by the front lens 6, and is reflected on the interference module 8. Finally, the interference signal is collected on the imaging camera 10 through the rear lens 9; the calibration light enters the system from the incident port of the collimator 5, and is folded 90 degrees by the collimator lens reflector 3 before entering the beam splitter 2. The split calibration light is filtered by the filter 4 and enters the front lens 6. After collimation and folding of the light path by the front lens 6, it is reflected on the interference module 8, and finally, the interference signal is collected on the imaging camera 10 through the rear lens 9.

[0039] like Figure 2As shown, the front lens mainly includes lens group 1 6-1, lens barrel 1 6-2, folding mirror 1 6-3, lens group 2 6-4, folding mirror 2 6-5, lens group 3 6-6, and lens barrel 2 6-7, wherein lens group 1 6-1 is coaxially arranged with the light entrance port of lens barrel 1 6-2, lens group 2 6-4 is coaxially arranged with the light entrance port of lens barrel 2 6-7, lens group 3 6-6 is coaxially arranged with the light exit port of lens barrel 2 6-7, and lens barrel 1 6-2 and lens barrel 2 6-7 are integrated into one through a flange.

[0040] like Figure 3 As shown, the rear lens mainly includes lens group four 9-1, lens barrel three 9-2, lens group five 9-3, lens barrel four 9-4, folding lens three 9-5, and lens group six 9-6. Among them, lens group four 9-1 is coaxially arranged with lens barrel three 9-2, lens group five 9-3 is coaxially arranged with the light entrance of lens barrel four 9-4, lens group six 9-6 is coaxially arranged with the light exit of lens barrel four 9-4, and lens barrel three 9-2 and lens barrel four 9-4 are integrated into one through a flange.

[0041] like Figure 4 As shown, a method for assembling and adjusting a Doppler asymmetric spatial heterodyne interferometer includes the following steps:

[0042] Step 1: Establish the installation benchmark;

[0043] Place theodolite 1 and theodolite 2 on a horizontal platform, adjust the level of the two theodolites and establish a reference. Place the autocollimator in front of theodolite 1, and use theodolite 1 to calibrate the output light of the autocollimator so that it coincides with the center of the theodolite crosshairs to establish the first reference state.

[0044] Step 2, install and adjust the front lens;

[0045] Lens group 1 6-1 and lens barrel 1 6-2, lens group 2 6-4, and lens group 3 6-6 and lens barrel 2 6-7 are respectively assembled and adjusted. First, lens group 1 6-1 is placed in lens barrel 1 6-2, and the position of the lens spherical center image is checked and calibrated using a centering device. After the requirements are met, lens group 1 6-1 is pressed and fixed. Then, lens group 2 6-4 and lens group 3 6-6 are placed in lens barrel 2 6-7, and the position of the lens spherical center image is checked and calibrated using a centering device. After the requirements are met, lens group 2 6-4 and lens group 3 6-6 are pressed and fixed.

[0046] Place the first lens barrel 6-2 and the second lens barrel 6-7 on the azimuth and elevation adjustment platforms, attach the first reference reflector to the reference surface of the entrance of the first lens barrel 6-2, and make the collimator emit light. Adjust the azimuth and elevation platforms so that the light returned by the reference reflector enters the center of the field of view of the autocollimator, thus establishing the second reference state.

[0047] Using the second reference state, install the folding mirror 1 6-3 on the lens barrel 1 6-2, and the star point plate on the light outlet flange of the lens barrel 1 6-2. Adjust the angle of the folding mirror 1 6-3 so that the light emitted by the collimator passes through the folding mirror 1 6-3 and converges to the center of the star point plate. Install the folding mirror 2 6-5 on the lens barrel 2 6-7, and the star point plate on the light outlet flange of the lens barrel 2 6-7. Adjust the angle of the folding mirror 2 6-5 so that the light emitted by the collimator passes through the folding mirror 2 6-5 and converges to the center of the star point plate. After installation is complete, glue the folding mirror 1 6-3 and the folding mirror 2 6-5 to secure them.

[0048] Fix the lens barrel 1 6-2 and the lens barrel 2 6-7 through the flange to keep the optical axis concentric, so as to realize the integrated assembly and calibration of the front lens;

[0049] Step 3, install and adjust the rear lens;

[0050] Adjust lens group 4 9-1 to lens barrel 3 9-2, lens group 5 9-3 and lens group 6 9-6 to lens barrel 4 9-4 respectively. First, place lens group 4 9-1 into lens barrel 3 9-2, use a centering device to check the position of the lens spherical center image and make corrections. Once the requirements are met, press and secure lens group 4 9-1. Then, place lens group 5 9-3 and lens group 6 9-6 into lens barrel 4 9-4, use a centering device to check the position of the lens spherical center image and make corrections. Once the requirements are met, press and secure lens group 5 9-3 and lens group 6 9-6.

[0051] Fix the lens barrel 3 9-2 and the lens barrel 4 9-4 through the flange to keep the optical axis concentric, so as to realize the integrated assembly and calibration of the rear lens;

[0052] Place the assembly of lens barrel 3 9-2 and lens barrel 4 9-4 on the azimuth and elevation adjustment platform, place theodolite 1 in front of the mounting flange of lens barrel 3 9-2, and theodolite 2 in front of the mounting flange of lens barrel 4 9-4, adhere reference reflector 1 to the surface of the mounting flange of lens barrel 3 9-2, and adhere reference reflector 2 to the surface of the mounting flange of lens barrel 4 9-4, use theodolite 1 to align reference reflector 1, adjust theodolite 1 so that its optical axis is perpendicular to the mounting flange of lens barrel 3 9-2, use theodolite 2 to align reference reflector 2, and adjust theodolite 2 so that its optical axis is perpendicular to the mounting flange of lens barrel 4 9-4, and establish the third reference state;

[0053] Using the established third reference state, install the folding mirror three 9-5 on the lens barrel four 9-4, adjust the angle of the folding mirror three 9-5 so that the crosshairs of the target emitted by theodolite one are imaged in the field of view of theodolite two, and move it to the center of the field of view. After the installation is completed, glue the folding mirror three 9-5 to fix it.

[0054] Step 4, assemble the overall components;

[0055] The front lens 6, the interference module 8, and the rear lens 9 are mounted on the load mounting plate 7 via flanges, and the filter 4 is mounted on the light entrance flange of the front lens 6.

[0056] Place load mounting plate 7 on the azimuth-pitch adjustment stage. Attach reference reflector 1 to the reference surface of load mounting plate 7. Allow the collimator to illuminate. Adjust the azimuth-pitch stage so that the light reflected by reference reflector 1 enters the center of the autocollimator's field of view, establishing the fourth reference state.

[0057] Using the established fourth reference state, install the folding mirror assembly 1 on the load mounting plate 7, adjust the angle of the folding mirror assembly 1, and let the light emitted by the collimator be reflected back to the center of the field of view of the self-collimating collimator through the front lens filter 4. After the installation is completed, glue the folding mirror assembly 1 to fix it.

[0058] Install the collimating mirror 5, collimating lens reflector 3, dichroic prism 2, and imaging camera 10 in the slots of the payload mounting plate 7. Adjust the collimating lens reflector 3 to move the imaging light spot to the center of the camera field of view. Adjust the camera defocus to make the imaging light spot the clearest image in the field of view.

[0059] After fixing all components, the Doppler asymmetric spatial heterodyne interferometer is assembled and adjusted.

Claims

1. A method for assembling and adjusting a Doppler asymmetric spatial heterodyne interferometer, characterized in that: It includes the following steps: Step 1: Establish the installation benchmark; Place theodolite 1 and theodolite 2 on a horizontal platform, adjust the level of the two theodolites and establish a reference. Use the light emitted by the calibrated autocollimator of theodolite 1 to establish a horizontal reference. The state must not be changed after the reference is established. Step 2, install and adjust the front lens; Place the first and second lens tubes on the azimuth and elevation adjustment platform, attach the reference reflector 1 to the light inlet flange of the first lens tube, make the collimator emit light, and adjust the azimuth and elevation platform so that the light returned by the reference reflector enters the center of the field of view of the autocollimator to establish the reference state. Adjust lens group 1 to lens barrel 1, lens group 2, and lens group 3 to lens barrel 2 respectively, and use a centering instrument to detect the position of the lens spherical center image for correction; Using the reference established by the self-collimating collimator and the lens barrel, install the folding mirror 1 on the lens barrel, and adjust the angle of the folding mirror 1 so that the light emitted by the collimator is focused to the center of the star point plate through the folding mirror 1. Using the reference established by the self-collimating collimator and the second lens barrel, install the second folding mirror on the second lens barrel and adjust the angle of the second folding mirror so that the light emitted by the collimator is focused to the center of the star point plate through the second folding mirror. Fix the lens barrel 1 and the lens barrel 2 through the flange to realize the integrated assembly and calibration of the front lens; Step 3, install and adjust the rear lens; Adjust lens group 4 to lens barrel 3, lens group 5, lens group 6 to lens barrel 4 respectively, use a centering instrument to check the position of the lens spherical center image and make corrections, fix lens barrel 3 and lens barrel 4 with flanges to keep the optical axis concentric; Place lens barrels 3 and 4 on the azimuth and elevation adjustment platforms, place theodolite 1 in front of the mounting flange of lens barrel 3, and theodolite 2 in front of the mounting flange of lens barrel 4. Attach reference reflectors 1 and 2 to the surfaces of the mounting flanges of lens barrels 3 and 4. Use theodolite 1 to align reference reflector 1, and adjust theodolite 1 so that its optical axis is perpendicular to the mounting flange of lens barrel 3. Use theodolite 2 to align reference reflector 2, and adjust theodolite 2 so that its optical axis is perpendicular to the mounting flange of lens barrel 4 to establish the reference state. Using the datum established by the theodolite and lens tubes three and four, install folding mirror three, adjust the angle of the folding mirror so that the crosshairs of the target emitted by theodolite one are imaged in the field of view of theodolite two, and move it to the center of the field of view; Step 4, assemble the overall components; Place the load mounting plate on the azimuth-pitch adjustment table, attach a reference reflector 1 to the reference surface of the load mounting plate, make the collimator emit light, and adjust the azimuth-pitch table so that the light returned by the reference reflector enters the center of the field of view of the autocollimator to establish the reference state; Using the reference established by the load mounting plate and the autocollimator, install the folding mirror assembly onto the load mounting plate. Adjust the angle of the folding mirror assembly so that the light emitted by the collimator is reflected back to the center of the autocollimator's field of view through the front lens filter. Install the collimator and the collimator lens reflector on the payload mounting plate, and install the camera on the payload mounting plate. Make the collimator emit light, and image it on the camera through the front lens, interferometer module, and rear lens. Adjust the collimator lens reflector to move the imaging light spot to the center of the camera's field of view. Adjust the camera defocus to make the imaging light spot the clearest image in the field of view. After fixing all components, the Doppler asymmetric spatial heterodyne interferometer is assembled and adjusted.

2. The method for assembling and adjusting a Doppler asymmetric spatial heterodyne interferometer according to claim 1, wherein: In step 2, the front lens is adjusted, and after the lens assembly is tested for conformity with a centering instrument, the lens assembly is fixed with glue.

3. The method for assembling and adjusting a Doppler asymmetric spatial heterodyne interferometer according to claim 1, wherein: In step 2, the front lens is adjusted, and the star point plate is matched and fixed with the exit port of the lens barrel, and the optical axes of the two are concentric.

4. The method for assembling and adjusting a Doppler asymmetric spatial heterodyne interferometer according to claim 1, wherein: During the overall assembly and adjustment in step 4, the front lens, rear lens, and collimating lens can be assembled and adjusted in parallel, and the remaining components can be assembled after the assembly and adjustment are completed.

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