Integration cavity greenhouse gas detection equipment capable of suppressing environmental noise

Abstract

The utility model discloses integral cavity greenhouse gas detection equipment capable of suppressing environmental noise, and belongs to the technical field of gas detection. The integrating cavity greenhouse gas detection equipment capable of suppressing environmental noise comprises a laser emission assembly and a light path adjustable input assembly arranged on an output light path of the laser emission assembly, the optical resonant cavity is arranged on an output light path of the light path adjustable input assembly; the information acquisition and processing assembly is arranged on an output light path of the optical resonant cavity; the light path adjustable input assembly comprises a first reflecting mirror, a second reflecting mirror, a Dove prism, off-axis parabolic mirror piezoelectric ceramics and a hollow roof prism reflecting mirror. According to the integral cavity greenhouse gas detection equipment capable of suppressing the environmental noise, reflected light is injected into the optical resonant cavity at a sufficient off-axis angle through the light path adjustable input assembly, so that the utilization rate of laser is greatly improved, sufficient off-axis of the off-axis optical resonant cavity is realized, and the problem of effectively suppressing the residual cavity mode noise is solved.

Description

Technical Field

[0001] This utility model relates to the field of gas detection technology, specifically to an integrating cavity greenhouse gas detection device for environmental noise suppression. Background Technology

[0002] Off-axis optical resonator output spectroscopy is a highly sensitive gas detection technique suitable for detecting trace gases in the atmosphere. Because the beam does not need to be strictly coaxial with the optical axis within the resonator, it offers advantages such as simple structure, system stability, and high integrability, making it a hot research topic in the field of atmospheric trace gas detection in recent years. However, when the laser beam is incident off-axis into the cavity, random fluctuations in the laser phase occur, generating cavity mode noise. Even with fully off-axis conditions, some residual cavity modes remain unsuppressed. Therefore, mode noise is a major factor affecting the measurement accuracy of the OA-ICOS system.

[0003] Off-axis optical resonator output spectroscopy obtains enhanced absorption signals by incidenting a beam off-axis into a high-precision cavity. However, residual cavity modes have always been a major noise source limiting sensitivity, posing certain challenges to the development of high-precision, high-sensitivity optical resonator spectroscopy measurement instruments. Utility Model Content

[0004] This invention provides an integrating cavity greenhouse gas detection device for environmental noise suppression, aiming to solve the key technical problems mentioned in the background art of how to fully off-axis the off-axis optical resonator and effectively suppress residual cavity mode noise.

[0005] To achieve the above objectives, this utility model provides the following technical solution: an integrating cavity greenhouse gas detection device for environmental noise suppression, comprising a laser emitting component, an adjustable optical path input component disposed at the output end of the laser emitting component, an optical resonant cavity disposed at the output end of the adjustable optical path input component, and an information acquisition and processing component disposed at the output end of the optical resonant cavity; the laser emitting component comprises a laser, a laser controller connected to the signal input end of the laser, an RF noise source device for injecting RF white noise into the laser, an optical isolator connected to the output end of the laser, an optical fiber connected to the output end of the optical isolator, and an optical fiber collimator fixedly installed at the end of the optical fiber; the optical resonant cavity comprises a cavity body, a front high-reflection mirror fixedly installed at the front end of the cavity body, and a rear high-reflection mirror fixedly installed at the rear end of the cavity body, wherein both the front and rear high-reflection mirrors are flat. The system includes a concave high-reflectivity mirror; the adjustable input component includes a first reflecting mirror disposed on the output path of the fiber optic collimator, a second reflecting mirror disposed on the reflected optical path of the first reflecting mirror, a Dowell prism disposed on the reflected optical paths of the first and second reflecting mirrors, an off-axis parabolic mirror disposed on the refracted optical path of the Dowell prism, a piezoelectric ceramic fixedly mounted on the back of the off-axis parabolic mirror, and a hollow roof prism reflecting mirror disposed on the reflected optical path of the front high-reflectivity mirror; the information acquisition and processing component includes a focusing lens, a photodetector disposed at the focal point of the focusing lens, and a terminal, the terminal being connected to the input end of the laser controller, the focusing lens being used to focus the transmitted signal output from the optical resonant cavity; the photodetector being used to convert the focused transmitted signal into an electrical signal and output it to the terminal, the terminal being used to acquire and process the electrical signal output by the photodetector and output a digital signal.

[0006] During gas measurement, the laser's operating temperature and current are adjusted by the laser controller. Radio frequency white noise is injected into the laser through a radio frequency noise source device, effectively suppressing residual cavity mode noise in the integrating cavity. The laser outputs unidirectional light through an optical isolator, which blocks back-propagating light, thus reducing background light interference. The laser then travels through an optical fiber collimator to the first reflecting mirror, which reflects the laser to the second reflecting mirror and the Dowell prism. The laser refracted and reflected by the Dowell prism is directly reflected onto the concave surface of the off-axis parabolic mirror. A portion of the laser is reflected by the first reflecting mirror to the second reflecting mirror, which then reflects it directly onto the concave surface of the off-axis parabolic mirror. The off-axis parabolic mirror then simultaneously reflects the laser from all paths to the plane of the front high-reflection mirror. The plane of the front high-reflection mirror reflects the reflected laser... The light is directed to the hollow roof prism reflector, where it is reversed 180 degrees and reflected again to the plane of the front high-reflection mirror. This achieves the goal of injecting the reflected light into the optical resonant cavity at a sufficiently off-axis angle, greatly improving the utilization rate of the laser. Piezoelectric ceramics are used to adjust the reflection angle of the off-axis parabolic mirror, which reflects back and forth between the front and rear high-reflection mirrors multiple times. Each time, a portion of the light is transmitted out. The transmitted light from each reflection is then converged and superimposed, finally outputting a strong beam with the same propagation direction, frequency, and phase. The focusing lens is used to focus the transmitted signal output from the optical resonant cavity. The photodetector is used to convert the focused transmitted signal into an electrical signal and output it to the terminal. The terminal is used to collect and process the electrical signal output from the photodetector and output a digital signal.

[0007] Preferably, the optical resonant cavity further includes an air inlet and an air outlet disposed on one side surface of the cavity, the air inlet being connected to an air pump, and the air outlet being connected to a mass flow controller.

[0008] Preferably, the hollow roof prism reflector includes two symmetrically arranged right-angle prism reflectors, and the reflective slopes of the two right-angle prism reflectors are coated with a high-reflectivity dielectric film.

[0009] Preferably, the adjustable optical path input component further includes a third reflector, which is disposed on the reflected optical path of the second reflector, and the Dowell prism is disposed on the reflected optical path of the third reflector for reflecting the laser to the Dowell prism.

[0010] Preferably, the base material of both the front high-reflection mirror 302 and the rear high-reflection mirror 303 is zinc selenide, the lens thickness is 5mm, the diameter is 30mm, and the concave surface curvature radius is 1000mm. The concave surfaces of both the front high-reflection mirror 302 and the rear high-reflection mirror 303 are coated with a high-reflection dielectric film, and the flat surfaces are coated with an anti-reflection film.

[0011] Preferably, the distance between the front high-reflection mirror 302 and the rear high-reflection mirror 303 is 160mm.

[0012] This environmental noise suppression integrating cavity greenhouse gas detection device adjusts the laser's operating temperature and current through a laser controller and injects radio frequency white noise into the laser via a radio frequency noise source device, effectively suppressing residual cavity mode noise in the integrating cavity. The laser outputs unidirectional light through an optical isolator, which blocks back-propagating light, thus reducing background light interference. The laser then travels through an optical fiber collimator to a first reflecting mirror, which in turn reflects the laser light to a second reflecting mirror and a Dowell prism. The laser light refracted and reflected by the Dowell prism is directly reflected onto the concave surface of an off-axis parabolic mirror, with a portion... The laser beam is reflected by the first mirror to the second mirror, and then directly reflected by the second mirror onto the concave surface of the off-axis parabolic mirror. The off-axis parabolic mirror then reflects the laser beams from each path simultaneously to the plane of the front high-reflection mirror. The plane of the front high-reflection mirror reflects the reflected laser beams to the hollow roof prism mirror. After passing through the hollow roof prism mirror, the reflected light is reversed 180 degrees and reflected again to the plane of the front high-reflection mirror. This achieves the purpose of injecting the reflected light into the optical resonant cavity at a fully off-axis angle, greatly improving the utilization rate of the laser and solving the problems of fully off-axis optical resonant cavity and effectively suppressing residual cavity mode noise. Attached Figure Description

[0013] Figure 1 A schematic diagram of the structure of Embodiment 1 of an integrating cavity greenhouse gas detection device for environmental noise suppression;

[0014] Figure 2 This is a schematic diagram of the structure of Example 2 of an integrating cavity greenhouse gas detection device for environmental noise suppression.

[0015] In the picture:

[0016] 1. Laser emitting assembly; 101. Laser; 102. Laser controller; 103. Radio frequency noise source device; 104. Optical isolator; 105. Optical fiber; 106. Fiber optic collimator;

[0017] 2. Adjustable optical path input component; 201. First reflector; 202. Second reflector; 203. Third reflector; 204. Dowell prism; 205. Off-axis parabolic mirror; 206. Piezoelectric ceramic; 207. Hollow roof prism reflector;

[0018] 3. Optical resonant cavity; 301. Cavity body; 302. Front high-reflection mirror; 303. Front high-reflection mirror;

[0019] 4. Information acquisition and processing components; 401. Focusing lens; 402. Photodetector; 403. Terminal;

[0020] 5. Air pump;

[0021] 6. Mass flow controller. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] Example 1

[0024] This embodiment provides an integrating cavity greenhouse gas detection device for environmental noise suppression, such as... Figure 1 and Figure 2As shown, the environmental noise suppression integrating cavity greenhouse gas detection device includes a laser emitting component 1, an optical path adjustable input component 2 disposed at the output end of the laser emitting component 1, an optical resonant cavity 3 disposed at the output end of the optical path adjustable input component 2, and an information acquisition and processing component 4 disposed at the output end of the optical resonant cavity 3. The laser emitting component 1 includes a laser 101, a laser controller 102 connected to the signal input end of the laser 101, an radio frequency noise source device 103 for injecting radio frequency white noise into the laser 101, an optical isolator 104 connected to the output end of the laser 101, an optical fiber 105 connected to the output end of the optical isolator 104, and an optical fiber collimator 106 fixedly installed at the end of the optical fiber. The optical path adjustable input component 2 includes a first reflector 201 disposed on the output path of the optical fiber collimator 106, a second reflector 202 disposed on the reflected optical path of the first reflector 201, and a second reflector 202 disposed on the reflected optical path of the first reflector 201 and the second reflector 202. The optical resonant cavity 3 includes a Dowell prism 204, an off-axis parabolic mirror 205 disposed on the refracting optical path of the Dowell prism 204, and a hollow roof prism reflector 207 disposed on the reflecting optical path of the front high-reflection mirror 302; the optical resonant cavity 3 includes a cavity 301, a front high-reflection mirror 302 fixedly installed at the front end of the cavity 301, and a rear high-reflection mirror 303 fixedly installed at the rear end of the cavity 301, wherein both the front high-reflection mirror 302 and the rear high-reflection mirror 303 are plano-concave high-reflection mirrors; the information acquisition and processing component 4 includes a focusing... The system includes a focal lens 401, a photodetector 402 positioned at the focal point of the focal lens 401, and a terminal 403. The terminal 403 is connected to the input of the laser controller 102. The focal lens 401 is used to focus the transmitted signal output from the optical resonant cavity 3. The photodetector 402 is used to convert the focused transmitted signal into an electrical signal and output it to the terminal 403. The terminal 403 is used to collect and process the electrical signal output by the photodetector 402 and output a digital signal.

[0025] During gas measurement, the operating temperature and current of the laser 101 are adjusted by the laser controller 102. Radio frequency white noise is injected into the laser 101 through the radio frequency noise source device 103, effectively suppressing residual cavity mode noise in the integrating cavity. The laser 101 outputs unidirectional light through the optical isolator 104, which blocks back-propagating light, thus reducing background light interference. The laser then travels through the fiber collimator 106 to the first reflecting mirror 201, which reflects the laser to the second reflecting mirror 202 and the Dowell prism 204. The laser refracted and reflected by the Dowell prism 204 is directly reflected onto the concave surface of the off-axis parabolic mirror 205. The laser reflected to the second reflecting mirror 202 is reflected again to the Dowell prism 204 and, after refraction and reflection, onto the concave surface of the off-axis parabolic mirror 205. The first reflecting mirror 201 reflects the laser to the second reflecting mirror 202, and then the off-axis parabolic mirror 205 simultaneously reflects the lasers from each path to... The plane of the front high-reflection mirror 302 reflects the reflected laser light to the hollow roof prism reflector 207. After passing through the hollow roof prism reflector 207, the reflected light is reversed 180 degrees and reflected again to the plane of the front high-reflection mirror 302, thereby coupling the laser into the integrating cavity and greatly improving the utilization rate of the laser. The piezoelectric ceramic 206 is used to adjust the reflection angle of the off-axis parabolic mirror 205. The laser light is reflected back and forth multiple times between the front high-reflection mirror 302 and the rear high-reflection mirror 303. Each time, a portion of the light is transmitted out. Then, the transmitted light from each time is converged and superimposed, and finally a strong beam with the same propagation direction, frequency and phase is output. The focusing lens 401 is used to focus the transmitted signal output by the optical resonant cavity 3. The photodetector 402 is used to convert the focused transmitted signal into an electrical signal and output it to the terminal 403. The terminal 403 is used to collect and process the electrical signal output by the photodetector 402 and output a digital signal.

[0026] In one embodiment, the optical resonant cavity 3 further includes an air inlet 3011 and an air outlet 3012 disposed on one side surface of the cavity 301. The air inlet 3011 is connected to an air pump 5, and the air outlet 3012 is connected to a mass flow controller 6.

[0027] In this embodiment, refer to Figure 1 and Figure 2 The air pump 5 controls the air intake and exhaust inside the cavity 301, and the mass flow controller 6 controls the internal pressure to ensure that the internal pressure is constant.

[0028] In one embodiment, the hollow roof prism reflector 207 includes two symmetrically arranged right-angle prism reflectors, and the reflective surfaces of the two right-angle prism reflectors are coated with a high-reflectivity dielectric film.

[0029] In this embodiment, refer to Figure 1 and Figure 2 The laser enters the reflection interface of one of the right-angle prism mirrors from the tail of the fiber 201. After being reflected by the high-reflectivity dielectric film of the other right-angle prism mirror, it is reversed 180 degrees and emitted out into the optical resonant cavity 3.

[0030] In one embodiment, the base material of both the front high-reflection mirror 302 and the rear high-reflection mirror 303 is zinc selenide, the lens thickness is 5mm, the diameter is 30mm, and the concave surface curvature radius is 1000mm. The concave surfaces of both the front high-reflection mirror 302 and the rear high-reflection mirror 303 are coated with a high-reflection dielectric film, and the flat surfaces are coated with an anti-reflection film.

[0031] In this embodiment, refer to Figure 1 and Figure 2 The concave surfaces of the front high-reflectivity mirror 302 and the rear high-reflectivity mirror 303 are coated with a high-reflectivity dielectric film with a reflectivity >99.98%, which helps to enhance the reflectivity. The flat surfaces are coated with an anti-reflection film to reduce reflected light.

[0032] In one embodiment, the distance between the front high-reflection mirror 302 and the rear high-reflection mirror 303 is 160 mm.

[0033] In this embodiment, refer to Figure 1 and Figure 2 The distance between the two lenses satisfies the condition for a stable resonant cavity, allowing light to travel back and forth multiple times within cavity 301 without the light spot spreading.

[0034] Example 2

[0035] Unlike Embodiment 1, the adjustable optical path input component 2 further includes a third reflector 203, which is disposed on the reflected optical path of the second reflector 202, and the Daowei prism 204 is disposed on the reflected optical path of the third reflector 203 for reflecting the laser to the Daowei prism 204.

[0036] In this embodiment, refer to Figure 2 The laser light reflected by the second reflector 202 is reflected by the third reflector 203 and then reflected by the Dowell prism 204. After refraction and reflection, it is projected onto the concave surface of the off-axis parabolic mirror 205.

[0037] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. An integral cavity greenhouse gas detection device for environmental noise suppression, comprising a laser emitting component (1), an optical path adjustable input component (2) disposed at the output end of the laser emitting component (1), an optical resonant cavity (3) disposed at the output end of the optical path adjustable input component (2), and an information acquisition and processing component (4) disposed at the output end of the optical resonant cavity (3). Its features are: The laser emitting assembly (1) includes a laser (101), a laser controller (102) connected to the signal input terminal of the laser (101), a radio frequency noise source device (103) for injecting radio frequency white noise into the laser (101), an optical isolator (104) connected to the output terminal of the laser (101), an optical fiber (105) connected to the output terminal of the optical isolator (104), and an optical fiber collimator (106) fixedly installed at the end of the optical fiber. The optical resonant cavity (3) includes a cavity (301), a front high-reflection mirror (302) fixedly installed at the front end of the cavity (301), and a rear high-reflection mirror (303) fixedly installed at the rear end of the cavity (301). Both the front high-reflection mirror (302) and the rear high-reflection mirror (303) are plano-concave high-reflection mirrors. The adjustable optical path input component (2) includes a first reflector (201) disposed on the output path of the fiber collimator (106), a second reflector (202) disposed on the reflected optical path of the first reflector (201), a Dowell prism (204) disposed on the reflected optical path of the first reflector (201), an off-axis parabolic mirror (205) disposed on the refracted optical path of the Dowell prism (204), a piezoelectric ceramic (206) fixedly installed on the back of the off-axis parabolic mirror (205), and a hollow roof prism reflector (207) disposed on the reflected optical path of the front high reflection mirror (302). The information acquisition and processing component (4) includes a focusing lens (401), a photodetector (402) located at the focal point of the focusing lens (401), and a terminal (403), wherein the terminal (403) is connected to the input end of the laser controller (102).

2. The ambient noise-rejected integrated cavity output spectrometer greenhouse gas detection apparatus of claim 1, wherein: The optical resonant cavity (3) also includes an air inlet (3011) and an air outlet (3012) disposed on one side surface of the cavity (301). The air inlet (3011) is connected to an air pump (5), and the air outlet (3012) is connected to a mass flow controller (6).

3. The ambient noise-rejected integrated cavity output spectrometer greenhouse gas detection apparatus of claim 1, wherein: The hollow roof prism reflector (207) includes two symmetrically arranged right-angle prism reflectors, and the reflective slopes of the two right-angle prism reflectors are coated with a high-reflectivity dielectric film.

4. The environmental noise suppression integrating cavity greenhouse gas detection device according to claim 1, characterized in that: The adjustable optical path input component (2) further includes a third reflector (203), which is disposed on the reflected optical path of the second reflector (202), and the Dowell prism (204) is disposed on the reflected optical path of the third reflector (203) for reflecting the laser to the Dowell prism (204).

5. The environmental noise suppression integrating cavity greenhouse gas detection device according to claim 1, characterized in that: The base material of both the front high-reflection mirror (302) and the rear high-reflection mirror (303) is zinc selenide. The lens thickness is 5mm, the diameter is 30mm, and the concave surface curvature radius is 1000mm. The concave surface of both the front high-reflection mirror (302) and the rear high-reflection mirror (303) is coated with a high-reflection dielectric film, and the flat surface is coated with an anti-reflection film.

6. The ambient noise-rejected integrated cavity output spectrometer greenhouse gas detection apparatus of claim 1, wherein: The distance between the front high-reflection mirror (302) and the rear high-reflection mirror (303) is 160 mm.

Images