A herriot cell optical path calibration device
By combining a visible light laser and a laser collimation module, precise calibration of the Herriot gas cell is achieved, solving the problems of high assembly difficulty and cost, and improving the accuracy and efficiency of the optical system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- YINIAN SENSOR TECH (SHENZHEN) CO LTD
- Filing Date
- 2025-07-24
- Publication Date
- 2026-06-16
Smart Images
Figure CN224365958U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of gas detection technology, and in particular to a Herriot gas cell optical path calibration device. Background Technology
[0002] The fundamental principle of TDLAS technology is Beer-Lamber's law, which states that the detection limit of this technology is directly affected by the optical path length. Herriot cells can achieve longer optical paths over shorter distances and have wide applications in laser absorption spectroscopy. Herriot cells rely on the back-and-forth reflection of the beam at both ends of the cavity to increase the optical path length; the more reflections, the longer the optical path. A high number of reflections enhances the detection performance of the technology but also increases the difficulty of assembling and adjusting the cell.
[0003] In the existing technology, the Herriot gas cell is a high-precision optical system. Its assembly mainly relies on the experience of engineers. Even slight deviations can bring huge errors to the optical system. In the field of laser absorption spectroscopy, the laser source commonly used is an invisible light source. Therefore, the light matching process often relies on optical imaging instruments such as infrared cameras, which increases production costs and light matching difficulty. Utility Model Content
[0004] This application provides a Herriot gas cell optical path calibration device, which achieves the following effect.
[0005] The Herriot gas cell optical path calibration device provided in this application adopts the following technical solution:
[0006] Box;
[0007] A laser collimation module is fixed to one side surface of the housing. The laser collimation module includes a cylindrical body, a non-visible light laser, a collimating lens, and an adjustment structure. The cylindrical body is used to sequentially fix the non-visible light laser, the collimating lens, and the adjustment structure, and the non-visible light laser is detachably connected to the cylindrical body. The adjustment structure is configured to adjust the spot size of the non-visible light laser after collimation by the collimating lens.
[0008] A coaxial beam-aligning module includes a visible light laser, an incident light adjustment mirror, a first aperture, a second aperture, an exit light adjustment mirror, and a detector. The visible light laser and the non-visible light laser are selectively connected to the cylindrical body. Both the incident light adjustment mirror and the exit light adjustment mirror are adjustablely mounted within the housing. The detector is located on the surface of the housing on the same side as the cylindrical body. The first aperture and the second aperture are parallel and spaced apart on the other side surface of the housing.
[0009] An air cell is fixed to the side surface of the housing and is on the same side as the first aperture. The air cell includes a light window arranged opposite to the light source for light to enter and exit. The incident light adjustment mirror and the outgoing light adjustment mirror are respectively used to reflect the incident light emitted by the coaxial optical module so that the incident light enters the air cell, and to receive the outgoing light reflected from the air cell and reflect it to be sensed by the detector.
[0010] By adopting the above technical solution, before the Herriot gas cell is put into operation, the laser collimation module is connected to a visible light laser, which allows the operator to visually adjust the spot size and divergence angle, as well as the positional angle relationship between the incident light adjustment mirror and the exit light adjustment mirror, through the laser collimation module. This ensures that after multiple reflections of the laser entering the Herriot gas cell, the spot will not overlap on the end face of the gas cell, thereby reducing interference noise caused by spot overlap. The coaxial beam alignment module obtains the distances of the optical window, the first aperture, and the second aperture relative to the housing through theoretical calculations. The first aperture and the second aperture... The two apertures determine the optical path and spot size for the Herriot cell to operate. By adjusting the laser collimation module, the incident light adjustment mirror, and the exit light adjustment mirror, the incident light emitted by the visible laser passes through the first and second apertures without obstruction, thus achieving pre-calibration of the Herriot cell. Maintaining the position and angle of the laser collimation module, the incident light adjustment mirror, and the exit light adjustment mirror as adjusted during the pre-calibration process, the non-visible laser is connected to the laser collimation module, thus achieving calibration of the Herriot cell.
[0011] Optionally, the adjustment structure includes a divergence angle adjustment component and a coaxial adjustment component. The divergence angle adjustment component is disposed on the surface of the cylinder, and the coaxial adjustment component is disposed circumferentially on the side of the cylinder.
[0012] By adopting the above technical solution, the divergence angle adjustment component controls the non-visible light laser or visible light laser to move along the axis of the cylinder and adjust it to the focal point of the collimating lens, so that the laser obtains the laser with the minimum divergence angle after being calibrated by the collimating lens; the coaxial adjustment component adjusts the axis of the laser to coincide with the axis of the collimating lens, so that the laser passes through the center of the collimating lens and is accurately projected onto the surface of the incident light adjustment mirror.
[0013] Optionally, a receiving cavity is formed inside the cylinder, and a moving block is fitted into the receiving cavity with a gap. The divergence angle adjusting member is connected to the moving block, and the coaxial adjusting member abuts against the moving block. The end of the moving block away from the surface of the cylinder is detachably connected to the visible light laser.
[0014] By adopting the above technical solution, the adjustment structure is avoided from directly adjusting the position angle of the visible light laser relative to the collimating lens. As a result, after the pre-calibration operation is completed, the position angle relationship of the non-visible light laser obtained during the pre-calibration process is lost because the visible light laser is separated from the laser collimation module, thus making it impossible to complete the calibration operation.
[0015] Optionally, a connecting seat is also provided between the laser collimation module and the housing. The connecting seat is hollow to form a through hole, and the inner diameter of one end of the through hole gradually decreases and engages with the collimating lens.
[0016] By adopting the above technical solution, the connector enables the laser collimation module to be conveniently and detachably connected to the housing, facilitating the maintenance of the collimation lens; the through hole restricts the installation position and angle of the collimation lens, and at the same time, due to the gradually narrowing inner diameter of the through hole, the inner wall of the through hole guides the collimation lens into the housing during installation, thereby reducing the assembly accuracy requirements.
[0017] Optionally, the connecting seat has protruding columns at opposite ends, and the columns are detachably connected to the housing and the laser collimation module, respectively.
[0018] By adopting the above technical solution, the column allows the connecting seat to be detachably connected to the housing and the laser collimation module, thereby facilitating the connection and disassembly of the laser collimation module to the housing.
[0019] Optionally, optical path reflector assemblies are respectively provided on opposite sides of the gas pool.
[0020] By adopting the above technical solution, during the Herriot gas cell pre-calibration process, the laser passes through the first aperture and the second aperture in sequence and projects a light spot onto the surface of the optical path reflector assembly away from the housing; during the Herriot gas cell operation, the back-to-back optical path reflector assemblies reflect the incident light multiple times and present a circularly distributed light spot array on the surface, and after a limited number of reflections, the laser is projected onto the surface of the outgoing light adjustment mirror.
[0021] Optionally, the gas pool includes a shaft cylinder, with threads provided at opposite ends of the shaft cylinder, and the optical path reflector assembly is threadedly connected to the shaft cylinder.
[0022] By adopting the above technical solution, the optical path reflector assembly is stably connected to the shaft cylinder. At the same time, by adjusting the pitch of the optical path reflector assembly and the shaft cylinder, the distance between the two back-to-back optical path reflector assemblies can be precisely adjusted, thereby adjusting the working optical path of the Herriot gas cell and the reflection path of the laser.
[0023] Optionally, the first aperture and the second aperture are located between the opposing optical path reflector assemblies and are engaged with the shaft cylinder. The surface of the shaft cylinder is provided with a limiting member, and the first aperture and the second aperture respectively abut against the limiting member.
[0024] By adopting the above technical solution, the shaft cylinder can be conveniently installed and disassembled, thereby realizing the quick replacement and fixation of the first and second aperture plates; the limiting component guides the installation position of the first and second aperture plates, and locks the position of the first and second aperture plates for stable installation.
[0025] Optionally, both the first aperture and the second aperture include multiple light-transmitting holes.
[0026] By adopting the above technical solution, the first and second apertures provide multiple calibration optical paths to achieve flexible calibration, while multiple light-passing holes allow the first aperture to work with the second aperture to calibrate different working modes of the Herriot gas cell.
[0027] Optionally, the enclosure is sealed, and the gas cell and laser collimation module are respectively configured to have gas introduced into them.
[0028] By adopting the above technical solution, the housing protects the incident light adjustment mirror and the output light adjustment mirror from dust pollution and interference in the external environment, thereby maintaining the precision of the incident light adjustment mirror and the output light adjustment mirror; the gas to be detected is introduced into the gas cell for detection, and the laser collimation module is introduced into the protective gas to avoid laser path deviation caused by uneven distribution of different components of gas in the air.
[0029] In summary, this application includes at least one of the following beneficial technical effects:
[0030] 1. The Herriot gas cell optical path calibration device is pre-calibrated by a visible light laser, so that the path of the calibration optical path can be observed by the human eye, thereby reducing production costs and assembly difficulty, and avoiding the need to use optical imaging instruments such as infrared cameras to directly calibrate the invisible light laser.
[0031] 2. Laser path calibration is completed by using a first aperture in conjunction with a second aperture, which facilitates operation and meets calibration accuracy requirements;
[0032] 3. The laser collimation module can be used to adjust the divergence angle and laser spot diameter of different lasers, thereby adjusting the laser to enter the gas cell with the minimum divergence angle and spot diameter. This avoids the laser spot diameter being too large and being blocked outside the gas cell, thus causing laser energy loss, and also avoids the laser spot area being too large, which would cause the laser spot to overlap after multiple reflections inside the gas cell and generate interference noise. Attached Figure Description
[0033] Figure 1 This is a schematic diagram of the overall structure of the Herriot gas cell optical path calibration device in one embodiment of this application;
[0034] Figure 2 This is a partial structural schematic diagram of the Herriot gas cell optical path calibration device in one embodiment of this application;
[0035] Figure 3 This is a partial structural schematic diagram of the Herriot gas cell optical path calibration device from another perspective in one embodiment of this application;
[0036] Figure 4 This is a schematic diagram of the optical path of the Herriot gas cell optical path calibration device according to one embodiment of this application;
[0037] Figure 5 This is a top view of the Herriot gas cell optical path calibration device according to one embodiment of this application;
[0038] Figure 6 yes Figure 5 Sectional view of AA;
[0039] Figure 7 This is an exploded view of the laser collimation module in one embodiment of this application;
[0040] Figure 8 This is an exploded view of the laser collimation module described in one embodiment of this application from another perspective;
[0041] Figure 9 This is a light spot distribution diagram on the surface of the optical path reflector assembly arranged on opposite sides in one embodiment of this application.
[0042] Explanation of reference numerals in the attached figures:
[0043] 1. Housing; 2. Laser collimation module; 21. Cylinder; 211. Receiving cavity; 212. Moving block; 22. Non-visible laser; 23. Collimating lens; 24. Adjustment structure; 241. Divergence angle adjustment component; 2411. Forward push screw; 2412. Backward pull screw; 242. Coaxial adjustment component; 25. Connecting seat; 251. Through hole; 252. Column; 3. Coaxial beam alignment module; 31. Visible laser; 32. Incident beam adjustment mirror; 33. Outgoing beam adjustment mirror; 34. First aperture; 35. Second aperture; 36. Light passage; 37. Detector; 4. Gas cell; 41. Optical window; 42. Optical path reflector assembly; 43. Shaft cylinder; 431. Limiting component. Detailed Implementation
[0044] The present application will be further described in detail below with reference to all the accompanying drawings.
[0045] This application discloses a Herriot gas cell optical path calibration device.
[0046] The basic principle of TDLAS technology is Beer-Lamber's law. According to Beer-Lamber's law, the detection limit of this technology is directly affected by the optical path length. Herriot gas cells can achieve longer optical paths over short distances and have wide applications in the field of laser absorption spectroscopy.
[0047] In the field of laser absorption spectroscopy, non-visible light bands are typically used to monitor the vibrational and rotational absorption lines of most molecules, especially gas molecules. The visible light band is only useful in specific applications, such as detecting substances with electronic transitions or inherent color. Therefore, the application scenarios for the visible light band are relatively narrow, and non-visible light bands are more commonly used. In TDLAS technology, tunable semiconductor lasers can precisely adjust the output wavelength to match specific absorption peaks of gas molecules and can scan wavelengths within a certain range to completely cover one or more absorption lines of gas molecules, thereby obtaining high-resolution gas absorption spectra.
[0048] Therefore, in the field of laser absorption spectroscopy, Herriot gas cells, which use non-visible light as the laser source, are commonly used, and tunable semiconductor lasers are commonly used as laser generating devices.
[0049] Please see Figure 1-3 The Herriot gas cell optical path calibration device provided in this application embodiment includes a housing 1, a laser collimation module 2, a coaxial optical alignment module 3, and a gas cell 4.
[0050] The housing 1 is square in shape, with the laser collimation module 2 and the gas cell 4 respectively located on adjacent sides of the housing 1. The coaxial beam alignment module 3 is located in the spatial optical path formed by the laser collimation module 2 and the gas cell 4.
[0051] Please refer to the following: Figure 6-8 The laser collimation module 2 includes a cylindrical body 21, a non-visible laser 22, a collimating lens 23, an adjustment structure 24, and a connecting seat 25. The cylindrical body 21 is fixed to one side surface of the housing 1 via the connecting seat 25.
[0052] The cylinder 21 has a cavity 211 inside, and a moving block 212 is fitted into the cavity 211 with a gap. One end of the moving block 212 away from the surface of the cylinder 21 is selectively connected to a visible light laser 31 and a non-visible light laser 22.
[0053] The adjustment structure 24 is used to adjust the divergence angle and spot size of the laser emitted by the visible light laser 31 and the non-visible light laser 22. The adjustment structure 24 includes a divergence angle adjustment component 241 disposed on the surface of the cylinder 21 and connected to the moving block 212, and a coaxial adjustment component 242 disposed on the side of the cylinder 21 and abutting against the moving block 212. Both the divergence angle adjustment component 241 and the coaxial adjustment component 242 are set screws.
[0054] The connector 25 is hollow to form a through hole 251. The inner diameter of one end of the through hole 251 tapers and engages with the collimating lens 23, and pillars 252 protrude at both ends. The connector 25 is detachably connected to the housing 1 and the laser collimating module 2.
[0055] In this embodiment, the non-visible laser 22 is a TO packaged laser with an output center wavelength of 1574nm, and its fast axis half-width angle is 25° and its slow axis half-width angle is also 25°; the collimating lens 23 is a high-order aspherical lens to reduce collimation error caused by aberrations, and its effective aperture is 2.2mm.
[0056] In this embodiment, the divergence angle adjustment component 241 includes a push screw 2411 that abuts against the moving block 212 and a pull screw 2412 that is screwed onto the moving block 212. The push screw 2411 and the pull screw 2412 cause the moving block 212 to move along the axis of the non-visible light laser 22, thereby changing the distance of the non-visible light laser 22 relative to the focal point of the collimating lens 23. When the non-visible light laser 22 is moved and deviates from the focal point of the collimating lens 23 by the push screw 2411 or the pull screw 2412, the divergence angle of the laser output by the non-visible light laser 22 after passing through the collimating lens 23 increases; when the non-visible light laser 22 is moved and approaches the focal point of the collimating lens 23, the divergence angle of the laser output by the non-visible light laser 22 after passing through the collimating lens 23 decreases.
[0057] In this embodiment, the coaxial adjustment member 242 is formed by three set screws evenly distributed at 120° on the surface of the cylinder 21 and abuts against the moving block 212, thereby adjusting the axis of the non-visible light laser 22 to coincide with the axis of the collimating lens 23; the non-visible light laser 22 is collimated by the divergence angle adjustment member 241 and the coaxial adjustment member 242, and the beam diameter of the output laser is 2.2mm, thereby minimizing the divergence angle of the laser and preventing the beam from being blocked or overlapping during propagation in the Herriot gas cell.
[0058] In other embodiments, by adjusting structure 24, the cross-sectional diameter of the laser spot during propagation can be reduced to 1-2 mm, ensuring that the laser spot will not be blocked or overlapped during propagation in the Herriot gas cell.
[0059] The coaxial light-adjusting module 3 includes a visible light laser 31, an incident light adjustment mirror 32, a first aperture 34, a second aperture 35, an outgoing light adjustment mirror 33, and a detector 37. The visible light laser 31 is detachably connected to the moving block 212, and the detector 37 is located on the same side surface of the housing 1 as the cylinder 21.
[0060] The incident light adjustment mirror 32 and the outgoing light adjustment mirror 33 are fixed inside the housing 1 and can rotate, so that the incident laser emitted by the visible light laser 31 enters the gas cell 4 and the outgoing laser emitted from the gas cell 4 is reflected to the detector 37 for sensing; the first aperture 34 and the second aperture 35 are arranged parallel to each other on the other side surface of the housing 1 to limit the optical path of the visible light laser for pre-calibration operation.
[0061] In this embodiment, the incident light adjustment mirror 32 and the outgoing light adjustment mirror 33 are respectively mounted on an adjustable mirror frame that can be tilted and rotated, and the adjustable mirror frame is fixedly connected to the inner wall of the housing 1.
[0062] Please see Figure 4 The first aperture 34 and the second aperture 35 are each provided with a plurality of light-transmitting holes 36. The light-transmitting holes 36 of the first aperture 34 and the second aperture 35 are combined to form an optical path that enables the Herriot gas cell to operate. The laser collimation module 2 adjusts the divergence angle and spot size of the laser emitted by the visible light laser 31 and adjusts the angle of the incident light adjustment mirror 32 so that the laser can pass through the light-transmitting holes 36 on the surface of the first aperture 34 and the light-transmitting holes 36 on the surface of the second aperture 35 in sequence and be projected onto the surface of the optical path reflector assembly 42 away from the surface of the housing 1, thus completing the pre-calibration operation of the Herriot gas cell.
[0063] In this embodiment, the laser band output by the visible light laser 31 can be any wavelength within the 400-760nm band, so that the laser can be distinguished by the human eye without relying on imaging instruments, thereby reducing production costs and light matching difficulties.
[0064] In this embodiment, both the visible light laser 31 and the non-visible light laser 22 are tunable semiconductor lasers, each with connection pins on its body. To achieve precise and stable installation, the moving block 212 is provided with a corresponding mating structure, that is, the surface of the moving block 212 has insertion holes that match the laser pins for initial electrical connection and positioning; then, pressure is applied by a pressure ring to firmly fix the laser body in place, thereby precisely limiting its final position.
[0065] Specifically, the non-visible laser 22 or the visible laser 31 is controlled by the divergence angle adjustment component 241 to move along the axis of the cylinder 21 and be adjusted to the focal point of the collimating lens 23. The coaxial adjustment component 242 is used to adjust the axis of the laser to coincide with the axis of the collimating lens 23, so that the laser passes through the center of the collimating lens 23, thereby minimizing the laser divergence angle and minimizing the laser spot size. This avoids the laser spot size exceeding the aperture of the optical window 41, causing part of the laser to be blocked outside the gas cell 4, resulting in laser energy loss and measurement errors. At the same time, it also avoids the laser spot size being too large, causing the laser spots to overlap and interfere after multiple reflections in the gas cell 4, thereby generating interference noise and interfering with the measurement process.
[0066] Please see Figure 5-6 The gas chamber 4 is fixed to the side surface of the housing 1 and is on the same side as the first aperture 34. The gas chamber 4 is formed by the cooperation of the optical path reflector assembly 42 and the shaft cylinder 43. One end of the shaft cylinder 43 is fixedly connected to the side surface of the housing 1, and the optical path reflector assembly 42 is screwed to both ends of it. The periphery of the optical path reflector assembly 42 near the housing 1 and the surface of the housing 1 covered by the projection of the optical path reflector assembly 42 are provided with light windows 41 for laser to enter and exit. The first aperture 34 and the second aperture 35 are engaged with the shaft cylinder 43 and abut against the limiting member 431 provided on the surface of the shaft cylinder 43, so that the first aperture 34 and the second aperture 35 are in the position determined by theoretical calculation between the optical path reflector assemblies 42 on opposite sides.
[0067] After completing the pre-calibration operation, maintain the position and angle of the laser collimation module 2, the incident light adjustment mirror 32, and the output light adjustment mirror 33 as adjusted during the pre-calibration process. Connect the non-visible laser 22 to the laser collimation module 2 to ensure that the laser output from the non-visible laser 22 after collimation by the laser collimation module 2 has the same position and direction as the visible laser 31. Thus, the non-visible light band laser output after collimation by the laser collimation module 2 is reflected by the incident light adjustment mirror 32 into the Herriot cell, and after multiple reflections in the Herriot cell along the pre-designed optical path, it leaves the Herriot cell and is then reflected by the output light adjustment mirror 33 to the detector 37, thereby completing the calibration operation of the Herriot cell.
[0068] Please see Figure 9 After the pre-calibration operation of the Herriot gas cell is completed, the first aperture 34 and the second aperture 35 are removed from the surface of the shaft cylinder 43 to obtain a light spot array arranged in a circle on the surface of the two optical path reflector assemblies 42 set opposite to each other; or after the calibration operation of the Herriot gas cell is completed and the Herriot gas cell is put into working condition, the light spot array arranged in a circle on the surface of the optical path reflector assembly 42 can be observed by optical imaging instruments such as infrared.
[0069] Please see Figure 1 The housing 1 is sealed and the gas pool 4 can be configured to allow gas to be introduced into the gas pool 4. Thus, in this embodiment, the light window 41 located on the surface of the housing 1 is made of sapphire material to allow lasers in the 0.25μm-5.5μm wavelength band to enter and to ensure the airtightness of the housing 1 and the gas pool 4. In other embodiments, the light window 41 can be made of materials such as zinc sulfide or spinel to allow lasers in different wavelength bands to pass through.
[0070] Specifically, the gas cell 4 also includes a shell with a sleeve 43. Both the surface of the shell and the surface of the cylinder 21 are connected to gas inlets. When the Herriot gas cell is in operation, the gas to be tested is delivered to the gas cell 4 through the gas inlets. The laser output by the non-visible laser 22 is reflected multiple times inside the gas cell 4 to measure the characteristics of the gas to be tested. When the Herriot gas cell is used in special scenarios, such as detecting low oxygen concentration gases, it is necessary to fill the containment cavity 211 with a protective gas, such as nitrogen, through the gas inlets to avoid air affecting the measurement accuracy.
[0071] The implementation principle of the Herriot gas cell optical path calibration device in this application embodiment is as follows: During the Herriot gas cell pre-calibration process, a visible light laser 31 is first connected to a laser collimation module 2. The visible light laser 31 outputs laser light, and the divergence angle of the laser light is adjusted by the adjustment structure 24 so that the laser spot size is minimized after being focused by the collimating lens 23 and projected onto the surface of the incident light adjustment mirror 32. Then, the operator visually adjusts the position and angle relationship of the incident light adjustment mirror 32 so that the laser light passes through the optical window 41 and enters the gas cell 4, and the laser light passes sequentially through the first... The light-transmitting holes 36 on the surface of the aperture 34 and the light-transmitting holes 36 on the surface of the second aperture 35 are ultimately projected onto the surface of the optical path reflector assembly 42 away from the housing 1 to present a light spot with a complete edge. Next, the first aperture 34 and the second aperture 35 are separated from the shaft cylinder 43, so that the surfaces of the two opposing optical path reflector assemblies 42 present a circumferentially distributed array of light spots, and laser light is emitted from the gas cell 4 and enters the housing 1. Finally, the position and angle relationship of the emitted light adjustment mirror 33 are adjusted so that the laser light is projected onto its surface and reflected to the detector 37 for sensing, thus completing the pre-calibration process.
[0072] During the Herriot cell calibration process, the positional and angular relationships of the adjustment structure 24, incident light adjustment mirror 32, first aperture 34, second aperture 35, and outgoing light adjustment mirror 33 obtained during the Herriot cell pre-calibration process are kept unchanged, so that the non-visible light laser 22 is connected to the laser collimation module 2, thus completing the calibration process.
[0073] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.
Claims
1. A Herriot gas cell optical path calibration device, characterized in that, include: Box (1); A laser collimation module (2) is fixed to one side surface of the housing (1). The laser collimation module (2) includes a cylinder (21), a non-visible light laser (22), a collimating lens (23), and an adjustment structure (24). The cylinder (21) is used to fix the non-visible light laser (22), the collimating lens (23), and the adjustment structure (24) in sequence, and the non-visible light laser (22) is detachably connected to the cylinder (21). The adjustment structure (24) is configured to adjust the spot size of the non-visible light laser (22) after collimation by the collimating lens (23). The coaxial beam-aligning module (3) includes a visible light laser (31), an incident light adjustment mirror (32), a first aperture (34), a second aperture (35), an outgoing light adjustment mirror (33), and a detector (37). The visible light laser (31) and the non-visible light laser (22) are selectively connected to the cylindrical body (21). The incident light adjustment mirror (32) and the outgoing light adjustment mirror (33) are both adjustablely disposed inside the housing (1). The detector (37) is located on the surface of the housing (1) on the same side as the cylindrical body (21). The first aperture (34) and the second aperture (35) are parallel and spaced apart on the other side surface of the housing (1). as well as An air cell (4) is fixed to the side surface of the housing (1) and is on the same side as the first aperture (34). The air cell (4) includes a light window (41) arranged opposite to each other for light to enter and exit. The incident light adjustment mirror (32) and the outgoing light adjustment mirror (33) are respectively used to reflect the incident light emitted by the coaxial optical module (3) so that the incident light enters the air cell (4) and to receive the outgoing light reflected from the air cell (4) and reflect it to be sensed by the detector (37).
2. The Herriot gas cell optical path calibration device according to claim 1, characterized in that: The adjustment structure (24) includes a divergence angle adjustment member (241) and a coaxial adjustment member (242). The divergence angle adjustment member (241) is disposed on the surface of the cylinder (21), and the coaxial adjustment member (242) is disposed circumferentially on the side of the cylinder (21).
3. The Herriot gas cell optical path calibration device according to claim 2, characterized in that: The cylinder (21) has a receiving cavity (211) inside, and a moving block (212) is fitted into the receiving cavity (211) with a clearance. The divergence angle adjusting member (241) is connected to the moving block (212), and the coaxial adjusting member (242) abuts against the moving block (212). The end of the moving block (212) away from the surface of the cylinder (21) is detachably connected to the visible light laser (31).
4. The Herriot gas cell optical path calibration device according to claim 1, characterized in that: A connecting seat (25) is also provided between the laser collimation module (2) and the housing (1). The connecting seat (25) is hollow to form a through hole (251). The inner diameter of one end of the through hole (251) gradually decreases and engages with the collimating lens (23).
5. The Herriot gas cell optical path calibration device according to claim 4, characterized in that: The connecting seat (25) has protruding columns (252) at both ends, and the columns (252) are detachably connected to the housing (1) and the laser collimation module (2).
6. The Herriot gas cell optical path calibration device according to claim 1, characterized in that: Optical path reflector assemblies (42) are respectively provided on opposite sides of the gas pool (4).
7. The Herriot gas cell optical path calibration device according to claim 6, characterized in that: The gas tank (4) includes a cylinder (43), and threads are provided at opposite ends of the cylinder (43). The optical path reflector assembly (42) is threadedly connected to the cylinder (43).
8. The Herriot gas cell optical path calibration device according to claim 7, characterized in that: The first aperture (34) and the second aperture (35) are located between the opposing optical path reflector assembly (42) and are engaged with the shaft cylinder (43). The surface of the shaft cylinder (43) is provided with a limiting member (431), and the first aperture (34) and the second aperture (35) respectively abut against the limiting member (431).
9. The Herriot gas cell optical path calibration device according to claim 8, characterized in that: Both the first aperture (34) and the second aperture (35) include multiple light-transmitting holes (36).
10. The Herriot gas cell optical path calibration device according to claim 1, characterized in that: The enclosure (1) is sealed, and the gas pool (4) and the laser collimation module (2) are respectively configured to have gas flowing into them.