Optical multi-pass cell system, gas absorption data detection method, and terminal device

Abstract

An optical multi-pass cell system, a gas absorption data detection method, and a terminal device. The optical multi-pass cell system comprises: an optical multi-pass cell (11), which comprises an input end (101) and an output end (102); and a driving mechanism (12), which is used for driving M sub-mirrors of the optical multi-pass cell (11) to perform periodic reciprocating motion in a Z-axis direction during each data collection process of a gas absorption data detection process, wherein the Z-axis direction is parallel to the optical axis of the optical multi-pass cell (11), M≥1, and the detection process comprises: when the optical multi-pass cell (11) is filled with a gas to be detected, a detection beam is inputted from the input end (101), is reflected multiple times in the optical multi-pass cell (11), and then forms an interference beam that is outputted from the output end (102). Optically noise-smoothed gas absorption data can be obtained, such that the sensitivity of detecting gas absorption data on the basis of an optical multi-pass cell system can be improved.

Description

Optical multi-pass cell system, gas absorption data detection method and terminal equipment Technical Field

[0001] This application relates to the field of optical multipass cell technology, and in particular to an optical multipass cell system, a gas absorption data detection method, and a terminal device. Background Technology

[0002] Improving the sensitivity of gas detectors generally requires the use of optical multipass cells with longer optical path lengths. However, the longer the optical path length, the larger the optical multipass cell becomes, and the sensitivity cannot be improved indefinitely by increasing the optical path length. Existing optical multipass cell technologies, such as Herriot and White cells, cannot meet the industrial demand for high-sensitivity, small-size gas detectors. Technical issues

[0003] One of the objectives of this application is to provide an optical multi-pass cell system, a gas absorption data detection method, a terminal device, and a storage medium to solve the problem that existing optical multi-pass cell technology cannot meet the industrial demand for high-sensitivity, small-volume gas detectors. Technical solutions

[0004] A first aspect of this application provides an optical multi-pass cell system, comprising:

[0005] An optical multipass cell, including an input and an output; and

[0006] A drive mechanism is used to drive the M sub-mirrors of the optical multipass cell to periodically reciprocate along the Z-axis direction during each data acquisition process in the gas absorption data detection process. The Z-axis direction is parallel to the optical axis of the optical multipass cell.

[0007] Where M≥1, the detection process is as follows: when the gas to be detected is filled into the optical multipass cell, the detection beam is input from the input end, and after multiple reflections in the optical multipass cell, an interference beam is formed and output from the output end. During the entire detection process, the wavelength of the detection beam changes within a preset wavelength range. During each data acquisition process, the wavelength of the detection beam is constant or changes within a preset wavelength modulation range.

[0008] A second aspect of this application provides a gas absorption data detection method, implemented based on an optical multi-pass cell system provided in the fourth implementation of the first aspect, the gas absorption data detection method comprising:

[0009] During each data acquisition process of the detection process, the drive mechanism is controlled to drive the M sub-mirrors of the optical multi-pass cell to periodically reciprocate along the Z-axis direction;

[0010] Obtain the actual light intensity of the interference beam output from the output end;

[0011] Based on the actual light intensity, obtain the spectral transmittance function of the gas to be detected;

[0012] Based on the spectral transmittance function, noise-smoothed gas absorption data of the gas to be detected are obtained.

[0013] A third aspect of this application provides a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the gas absorption data detection method provided in the second aspect of this application.

[0014] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the gas absorption data detection method provided in the second aspect of this application. Beneficial effects

[0015] The first aspect of this application provides an optical multi-pass cell system including an optical multi-pass cell and a driving mechanism. In each data acquisition process of the gas absorption data detection process, the driving mechanism drives M (M≥1) of the sub-mirrors of the optical multi-pass cell to periodically reciprocate along the Z-axis direction parallel to the optical axis of the optical multi-pass cell. Without significantly increasing the volume of the optical multi-pass cell system, interference beams at different positions of the M sub-mirrors can be obtained at the output end. Based on these interference beams, gas absorption data with smooth optical noise can be obtained, thereby improving the sensitivity of gas absorption data detection based on the optical multi-pass cell system.

[0016] The second aspect of this application provides a gas absorption data detection method. During each data acquisition process in the detection process, a control drive mechanism drives M sub-mirrors of an optical multi-pass cell to periodically reciprocate along the Z-axis direction. Interference beams are obtained at the output end when the M sub-mirrors are at different positions. Based on the actual light intensity of these interference beams, the spectral transmittance function of the gas to be detected is obtained. Thus, gas absorption data of the gas to be detected with smoothed optical noise can be obtained according to the spectral transmittance function.

[0017] It is understood that the beneficial effects of the third and fourth aspects mentioned above can be found in the relevant descriptions in the second aspect above, and will not be repeated here. Attached Figure Description

[0018] To more clearly illustrate the technical applications in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 is a schematic diagram of the structure of the first type of optical multipass cell provided in Embodiment 1 of this application;

[0020] Figure 2 is a schematic diagram of the structure of the second type of optical multipass cell provided in Embodiment 1 of this application;

[0021] Figure 3 is a schematic diagram of the structure of the third type of optical multipass cell provided in Embodiment 1 of this application;

[0022] Figure 4 is a structural schematic diagram of the fourth type of optical multipass cell provided in Embodiment 1 of this application;

[0023] Figure 5 is a structural schematic diagram of the fifth type of optical multipass cell provided in Embodiment 1 of this application;

[0024] Figure 6 is a structural schematic diagram of the sixth type of optical multipass cell provided in Embodiment 1 of this application;

[0025] Figure 7 is a flowchart illustrating the gas absorption data detection method provided in Embodiment 2 of this application. Embodiments of the present invention

[0026] In the following description, specific details such as particular device structures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known devices, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0027] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0028] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0029] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0030] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0031] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0032] Example 1

[0033] This application provides an optical multi-pass cell system, including:

[0034] An optical multipass cell, including an input and an output; and

[0035] The drive mechanism is used to drive the M sub-mirrors of the optical multipass cell to move back and forth periodically along the Z-axis direction during each data acquisition process in the gas absorption data detection process. The Z-axis direction is parallel to the optical axis of the optical multipass cell.

[0036] Where M≥1, the detection process is as follows: when the gas to be detected is filled into the optical multipass cell, the detection beam is input from the input end, and after multiple reflections in the optical multipass cell, an interference beam is formed and output from the output end. During the entire detection process, the wavelength of the detection beam changes within a preset wavelength range. During each data acquisition process, the wavelength of the detection beam is constant or changes within a preset wavelength modulation range.

[0037] In applications, the structure of the optical multipass cell can be configured according to actual needs, and the number of sub-mirrors in the optical multipass cell is greater than or equal to M. The driving mechanism can be based on piezoelectric ceramic or electromagnetic actuators. During the detection process, the wavelength of the detection beam varies within a preset wavelength range, and the wavelength of the detection beam is controlled to remain constant or vary within a preset wavelength modulation range during each data acquisition. Therefore, during each data acquisition, the spectral transmittance function can be obtained by signal processing based on the actual light intensity of the interference beam corresponding to each wavelength of the detection beam output from the output terminal. Both the preset wavelength range and the preset wavelength modulation range can be set according to actual needs. For example, the preset wavelength range can be 0.2µm to 12µm from ultraviolet wavelength to mid-infrared wavelength, and the wavelength of the detection beam modulated within the preset wavelength modulation range remains within the preset wavelength range.

[0038] The optical multi-pass cell system provided in this application, by driving M sub-mirrors to periodically reciprocate along the Z-axis during each data acquisition process of the gas absorption data detection process, can change the distance between the optical center of the sub-mirrors and their corresponding main mirrors, thereby changing the single optical path of the detection beam when reflected between the M sub-mirrors and their corresponding main mirrors. As a result, interference beams can be obtained at the output end when the M sub-mirrors are at different positions. Based on these interference beams, optically noise-smoothed gas absorption data can be obtained, thereby improving the sensitivity of the optical multi-pass cell system when detecting gas absorption data.

[0039] As shown in Figure 1, in one embodiment, a first optical multiplexer system is provided, including an optical multiplexer 11 and a driving mechanism 12. The optical multiplexer 11 includes:

[0040] Input terminal 101 is used to input the probe beam;

[0041] Output terminal 102 is used to output an interference beam;

[0042] Principal concave mirror 103; and

[0043] The first sub-reflector 104 and the second sub-reflector 105 are both concave mirrors. The reflecting surface of the main concave mirror 103 is opposite to and spaced apart from the reflecting surfaces of the first sub-reflector 104 and the second sub-reflector 105 to form a reflecting cavity. The optical axis 106 of the reflecting cavity is perpendicular to the focal plane of the main concave mirror 103.

[0044] Both the input terminal 101 and the output terminal 102 are located on the main concave reflector 103;

[0045] The drive mechanism 12 is used to drive the first sub-reflector 104 to move back and forth periodically along the Z-axis direction during each data acquisition process in the gas absorption data detection process. The Z-axis direction is parallel to the optical axis 106.

[0046] The detection process is as follows: when the gas to be detected is filled into the reflection cavity of the optical multipass cell 11, the detection beam is input from the input end 101, and after multiple reflections in the optical multipass cell 11, it forms an interference beam and is output from the output end 102. During the entire detection process, the wavelength of the detection beam changes within a preset wavelength range. During each data acquisition process, the wavelength of the detection beam is constant or changes within a preset wavelength modulation range.

[0047] In applications, the output terminal 102 can be located on the main concave reflector 103, the first sub-reflector 104, or the second sub-reflector 105. Figure 1 exemplarily shows that the output terminal 102 is located on the main concave reflector 103. The first sub-reflector 104 and the second sub-reflector 105 can be the same size or different sizes, depending on actual needs. The drive mechanism 12 can be used to drive the first sub-reflector 104 or the second sub-reflector 105 individually, or it can be used to drive the first sub-reflector 104 and the second sub-reflector 105 simultaneously. When the drive mechanism 12 drives the first sub-reflector 104 and the second sub-reflector 105 simultaneously, the drive mechanism 12 can include two drivers for driving the first sub-reflector 104 and the second sub-reflector 105 respectively.

[0048] Figure 1 shows, for example, an output terminal 102 disposed on the main concave reflector 103, and a drive mechanism 12 used to drive the first sub-reflector 104 to move independently.

[0049] This application provides an optical multipass cell including a main concave reflector and two sub-reflectors. During each data acquisition process in the gas absorption data detection process, at least one of the two sub-reflectors of the optical multipass cell is driven by a driving mechanism to periodically reciprocate along the Z-axis direction parallel to the optical axis of the optical multipass cell. Without significantly increasing the volume of the optical multipass cell system, interference beams at different positions of the M sub-reflectors can be obtained at the output end. Based on these interference beams, gas absorption data with smoothed optical noise can be obtained, thereby improving the sensitivity of gas absorption data detection based on the optical multipass cell system.

[0050] As shown in Figures 2, 3, 4, or 5, in one embodiment, a second optical multipass cell system is provided, including an optical multipass cell 21 and a driving mechanism 22. The optical multipass cell 21 includes:

[0051] Input terminal 201 is used to input the probe beam;

[0052] Output terminal 202 is used to output an interference beam;

[0053] 203, main concave reflector;

[0054] The primary plane mirror 204 and the primary concave mirror 203 have their reflecting surfaces opposite to and spaced apart from each other to form a reflecting cavity. The optical axis 206 of the reflecting cavity is perpendicular to the focal plane 205 of the primary concave mirror 203.

[0055] N sub-reflectors are set on the main plane reflector 204, and the reflecting surfaces of the N sub-reflectors are set facing the main concave reflector 203.

[0056] Where N≥M, input terminal 201 and output terminal 202 are located on the main plane reflector 204;

[0057] The drive mechanism 22 is used to drive at least one sub-reflector to periodically reciprocate along the Z-axis direction during each data acquisition process in the gas absorption data detection process, the Z-axis direction being parallel to the optical axis 206.

[0058] The detection process is as follows: when the gas to be detected is filled into the reflection cavity of the optical multipass cell 21, the detection beam is input from the input end 201, and after multiple reflections in the optical multipass cell 21, it forms an interference beam and is output from the output end 202. During the entire detection process, the wavelength of the detection beam changes within a preset wavelength range. During each data acquisition process, the wavelength of the detection beam is constant or changes within a preset wavelength modulation range.

[0059] In applications, the number of N and the type of reflecting surface can be set according to actual needs, for example, 1, 2, 3, 4. Input terminal 201 can be located on the main concave reflector 203 or the main planar reflector 204, and output terminal 202 can be located on the main concave reflector 203, the main planar reflector 204, or any sub-reflector. Figures 2, 3, 4, and 5 exemplarily show that both input terminal 201 and output terminal 202 are located on the main planar reflector 204. The drive mechanism 22 can be used to drive the movement of any one sub-reflector individually, or it can be used to drive the movement of multiple sub-reflectors simultaneously. When the drive mechanism 22 drives multiple sub-reflectors simultaneously, it can include multiple drivers for driving the movement of each sub-reflector separately.

[0060] Figure 2 shows an example where N=1, that is, the optical multi-pass cell 21 includes a first sub-reflector 207. The first sub-reflector 207 is a planar reflector with an area smaller than that of the main planar reflector 204. The tilt angle between the normal of the first sub-reflector 207 and the normal of the main planar reflector 204 is θ1 and the tilt angle θ1 is not zero. The drive mechanism 22 is used to drive the first sub-reflector 207 to move.

[0061] Figure 3 illustrates an example where N=2, meaning the optical multipass cell 21 includes a first sub-reflector 207 and a second sub-reflector 208. Both the first sub-reflector 207 and the second sub-reflector 208 are planar mirrors with an area smaller than that of the main plane mirror 204. The tilt angle between the normal of the first sub-reflector 207 and the normal of the main plane mirror 204 is θ1 and the tilt angle θ1 is not zero. The normal of the second sub-reflector 208 is parallel to the normal of the main plane mirror 204. The second sub-reflector 208 and the first sub-reflector 207 are symmetrically and separately arranged about the origin 209, which is the intersection of the optical axis 206 on the focal plane 205. The drive mechanism 22 is used to drive the second sub-reflector 208 to move.

[0062] Figure 4 illustrates an example where N=2, meaning the optical multipass cell 21 includes a first sub-reflector 207 and a second sub-reflector 208. Both the first sub-reflector 207 and the second sub-reflector 208 are planar mirrors with an area smaller than that of the main plane mirror 204. The tilt angle between the normal of the first sub-reflector 207 and the normal of the main plane mirror 204 is θ1 and the tilt angle θ1 is not zero. The normal of the second sub-reflector 208 is parallel to the normal of the main plane mirror 204. The second sub-reflector 208 and the first sub-reflector 207 are symmetrically arranged and adjacent to each other about the origin 209, which is the intersection of the optical axis 206 on the focal plane 205. The driving mechanism 22 is used to simultaneously drive the first sub-reflector 207 and the second sub-reflector 208 to move.

[0063] Figure 5 illustrates an example where N=2, meaning the optical multipass cell 21 includes a first sub-reflector 207 and a second sub-reflector 208. Both the first sub-reflector 207 and the second sub-reflector 208 are planar mirrors with an area smaller than that of the main plane mirror 204. The tilt angle between the normal of the first sub-reflector 207 and the normal of the main plane mirror 204 is θ1 and the tilt angle θ1 is not zero. The tilt angle between the normal of the second sub-reflector 208 and the normal of the main plane mirror 204 is θ2 and the tilt angle θ2 is not zero. The second sub-reflector 208 and the first sub-reflector 207 are symmetrically arranged and adjacent to each other about the origin 209, which is the intersection of the optical axis 206 on the focal plane 205. The driving mechanism 22 is used to simultaneously drive the first sub-reflector 207 and the second sub-reflector 208 to move.

[0064] In applications, tilt angles θ1 and θ2 can be equal or unequal. The first sub-reflector 207 and the second sub-reflector 208 shown in Figure 5 can be replaced by a single roof prism. Compared to simultaneously driving two independent sub-reflectors, the drive mechanism 22 provides greater stability during the movement of the roof prism.

[0065] In an embodiment of the present application, an optical multipass cell including a main concave mirror, a main plane mirror, and N sub - mirrors is provided. During each data acquisition process in the detection process of gas absorption data, based on a driving mechanism, M of the N sub - mirrors of the optical multipass cell are driven to move periodically back and forth along the Z - axis direction parallel to the optical axis of the optical multipass cell. Without significantly increasing the volume of the optical multipass cell system, interference beams at different positions of the M sub - mirrors can be obtained at the output end. Based on these interference beams, gas absorption data with smoothed optical noise can be obtained, thereby improving the sensitivity when detecting gas absorption data based on the optical multipass cell system.

[0066] As shown in FIG. 6, in one embodiment, a third optical multipass cell system is provided, including an optical multipass cell 31 and a driving mechanism 32. The optical multipass cell 31 includes:

[0067] An input end 301 for inputting a detection beam;

[0068] An output end 302 for outputting an interference beam;

[0069] A main concave mirror 303 with a focal length of f, a radius of curvature of R, and having aberration;

[0070] A main plane mirror 304, the distance from the reflecting surface of the main plane mirror 304 to the optical center of the main concave mirror 303 is L1=(1 + x1)f, - 1 < x1 < 1; and

[0071] A sub - mirror 305, the sub - mirror 305 is a concave mirror with a focal length of f0, a radius of curvature of R0, and is disposed on the main plane mirror 304. The area of the positive projection of the reflecting surface of the sub - mirror 305 on the reflecting surface of the main plane mirror 304 is smaller than the area of the reflecting surface of the main plane mirror 304. The distance from the optical center of the sub - mirror 305 to the optical center of the main concave mirror 303 is L2=(1 + x2)f, R0 = mR, - 1 < x2 < 1, x1 and x2 are not both 0, m > 0;

[0072] Among them, the input end 301 and the output end 302 are both disposed on the main concave mirror 303. The reflecting surface of the main concave mirror 303 is opposite to and spaced from the reflecting surfaces of the main plane mirror 304 and the sub - mirror 305 to form a reflection cavity. The optical axis 306 of the reflection cavity is perpendicular to the reflecting surface of the main plane mirror 304 and passes through the optical center and the focus of the main concave mirror 303;

[0073] The driving mechanism 12 is used to drive the sub - mirror 305 to move periodically back and forth along the Z - axis direction during each data acquisition process in the detection process of gas absorption data, and the Z - axis direction is parallel to the optical axis 306;

[0074] The detection process is as follows: when the gas to be detected is filled into the reflection cavity of the optical multipass cell 31, the detection beam is input from the input end 301, and after multiple reflections in the optical multipass cell 31, an interference beam is formed and output from the output end 302. During the entire detection process, the wavelength of the detection beam changes within a preset wavelength range. During each data acquisition process, the wavelength of the detection beam is constant or changes within a preset wavelength modulation range.

[0075] In applications, input terminal 301 can be set on main concave reflector 303 or main planar reflector 304, and output terminal 302 can be set on main concave reflector 303, main planar reflector 304 or sub-reflector 305. Figure 6 shows, for example, that both input terminal 301 and output terminal 302 are set on main concave reflector 303.

[0076] This application provides an optical multi-pass cell comprising a main concave reflector, a main planar reflector, and sub-reflectors. During each data acquisition process in the gas absorption data detection process, the sub-reflectors are driven by a driving mechanism to periodically reciprocate along the Z-axis direction parallel to the optical axis of the optical multi-pass cell. This allows interference beams from M sub-reflectors at different positions to be obtained at the output end without significantly increasing the volume of the optical multi-pass cell system. Based on these interference beams, gas absorption data with smoothed optical noise can be obtained, thereby improving the sensitivity of gas absorption data detection based on the optical multi-pass cell system.

[0077] In applications, the input end can be a fiber optic collimator with a pigtail, a fiber optic collimator array, a light-transmitting aperture or an open angle on the primary reflector, or a direct connection to the light-emitting device via optical fiber. The output end can also be a fiber optic collimator with a pigtail, a fiber optic collimator array, a light-transmitting aperture or an open angle on the primary or secondary reflector, or a direct connection to the photodetector via optical fiber. Light-transmitting apertures and open angles are suitable for incoherent detection beams with large divergence angles. For coherent detection beams with small divergence angles, such as lasers, a fiber optic collimator with a pigtail is selected as the optical input end, and a fiber optic collimator with a pigtail is selected as the output end accordingly. Alternatively, a photodetector can be chosen to directly receive the beam.

[0078] In applications, the input and output terminals can be overlapped to form a single input / output terminal, which is located on the main reflector or the sub-reflector.

[0079] Alternatively, the input and output terminals can be set separately and both can be located on the main reflector or the sub-reflector;

[0080] Alternatively, the input and output terminals can be set separately, with the input terminal located on the main reflector and the output terminal located on the sub-reflector, or the output terminal being a sub-reflector.

[0081] Alternatively, the input and output terminals can be set separately, with the input terminal set on the sub-reflector and the output terminal set on the main reflector, or the output terminal set on the main reflector.

[0082] In applications, the input and output terminals can be located at the same position or separately. When the input and output terminals are located at the same position, they are considered the same entity and are defined as the input / output terminal, which can be located on the main reflector or any sub-reflector. When the input and output terminals are located separately, they can be located on the same reflector or on different reflectors. When the output terminal is the main reflector or sub-reflector itself, the output terminal includes all reflection areas of the main reflector or sub-reflector.

[0083] In applications, the drive mechanism may include a motor and a driver. The motor is mechanically connected to the sub-reflector that needs to be driven, and the driver is electrically connected to the motor to drive its movement. The driver may be a piezoelectric ceramic driver, a micro-motor system driver, a magnetostrictive driver, or a voice coil motor driver.

[0084] In one embodiment, the Z-axis direction includes a parallel and opposite positive Z-axis direction and a negative Z-axis direction;

[0085] The position change of the sub-mirror when it moves along the positive Z-axis is a positive value;

[0086] The position change of the sub-mirror when it moves along the negative Z-axis is a negative value;

[0087] When M sub-mirrors periodically reciprocate along the Z-axis,

[0088] Where δ represents the sum of the position changes of the M sub-mirrors in the Z-axis direction, and λ represents the wavelength of the probe beam. During the entire detection process, λ is a variable that varies within a preset wavelength range. During each data acquisition process, λ remains constant or varies within a preset wavelength modulation range.

[0089] In applications, the sum of the positional changes of all sub-mirrors driven by the drive mechanism in the Z-axis direction ranges from 0.25 to 10 times the wavelength of the probe beam, and can be set according to actual needs.

[0090] Example 2

[0091] This application provides a gas absorption data detection method based on any of the optical multi-pass cell systems in Embodiment 1. The gas absorption data detection method can be executed by the processor of the terminal device when running a computer program with corresponding functions. In each data acquisition process of the detection process, the drive mechanism is controlled to drive the M sub-reflectors of the optical multi-pass cell to move periodically back and forth along the Z-axis. The interference beams of the M sub-reflectors at different positions are obtained at the output end. Based on the actual light intensity of these interference beams, the spectral transmittance function of the gas to be detected is obtained. Thus, the gas absorption data of the gas to be detected with smoothed optical noise can be obtained according to the spectral transmittance function. By using micro-motion optical components (i.e., the drive mechanism and the sub-reflectors it drives), the sensitivity of the terminal device can be effectively improved by more than 10 times.

[0092] In applications, optical noise refers to the fluctuation in light intensity received at the output of an optical multipass cell when the gas to be detected is absent, which varies with the wavelength of the probe beam. This fluctuation manifests as light intensity changing with wavelength, hence the term optical noise. Since absorption spectroscopy infers the concentration of the gas to be detected by scanning the intensity change of the probe beam after it passes through an optical multipass cell containing the gas, the presence of optical noise during the wavelength scan causes variations in the output light intensity, resulting in spurious absorption peaks. The level of optical noise determines the lower limit of gas concentration that the terminal device can detect. By reducing optical noise, the lower limit of gas concentration that the terminal device can detect can be lowered, thereby improving the sensitivity of the terminal device.

[0093] In the application, the terminal device may include a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the gas absorption data detection method. The processor may include a drive mechanism control unit and a signal processing unit, and may also include a laser drive unit. The drive mechanism control unit is electrically connected to the drive mechanism to control the operation of the drive mechanism. The signal processing unit is electrically connected to an optical detection device (e.g., a photodetector or spectrometer) to acquire the light intensity signal or spectral signal detected by the optical detection device, and to perform signal processing to obtain data such as the spectral transmittance function and gas absorption data (e.g., concentration) of the gas to be detected.

[0094] In applications, at least two of the drive mechanism control unit, signal processing unit, and laser drive unit can be integrated into one processing unit, or each unit can exist physically separately. Furthermore, the specific names of the laser drive unit and signal processing unit are merely for ease of distinction and are not intended to limit the scope of protection of this invention. The terminal device can also be integrated with at least one of the optical multipass cell system, laser, and optical detection equipment into a single device (e.g., a gas detector), and can be configured according to the positions of the input and output terminals of the optical multipass cell system in accordance with actual needs.

[0095] In applications, the memory may be an internal storage unit of the terminal device in some embodiments, such as a hard disk or RAM, specifically the processor's memory. In other embodiments, the memory may be an external storage device of the terminal device, such as a plug-in hard disk, a smart media card (SMC), a secure digital card (SD), a flash card, etc. Furthermore, the memory may include both internal and external storage units of the terminal device. The memory is used to store the operating system, applications, boot loader, data, and other programs, such as the program code of computer programs. The memory can also be used to temporarily store data that has been output or will be output.

[0096] In applications, the laser driver unit and signal processing unit can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor.

[0097] In applications, the laser can be any type of tunable laser, such as Fabry-Perot lasers, distributed feedback semiconductor lasers, distributed Bragg reflector lasers, vertical-cavity surface-emitting lasers, and external cavity tunable semiconductor lasers.

[0098] As shown in Figure 7, the gas absorption data detection method provided in this application includes the following steps S1 to S4:

[0099] Step S1: During each data acquisition process in the detection process, the control drive mechanism drives the M sub-mirrors of the optical multi-pass cell to move back and forth periodically along the Z-axis.

[0100] Step S2: Obtain the actual light intensity of the interference beam output from the output end;

[0101] Step S3: Obtain the spectral transmittance function of the gas to be detected based on the actual light intensity;

[0102] Step S4: Obtain the gas absorption data of the gas to be detected with noise smoothed according to the spectral transmittance function.

[0103] In the application, step S1 is executed by the drive mechanism control unit; steps S2 to S4 are executed by the signal processing unit, which acquires the actual light intensity of the interference beam output from the output end based on the photodetector, and then performs signal processing to obtain the spectral transmittance function and gas absorption data of the gas to be detected.

[0104] In one embodiment, during the execution of step S1, the laser driving unit controls the laser to output a probe beam to the input terminal, and the wavelength of the probe beam is constant or varies within a preset wavelength modulation range.

[0105] In one embodiment, the gas absorption data detection method is based on the maximum-minimum method of direct absorption, and the wavelength of the detection beam is constant during each data acquisition process;

[0106] Step S1 includes: during each data acquisition process in the detection process, controlling the drive mechanism to drive the M sub-mirrors of the optical multi-pass cell to periodically reciprocate along the Z-axis direction, so that the sum of the position changes of the M sub-mirrors in the Z-axis direction is within the range of 0.5 to 10 times the wavelength of the detection beam, that is...

[0107] Step S2 includes: during the periodic reciprocating motion of the M sub-mirrors along the Z-axis for one or more cycles, obtaining the actual light intensity of the interference beam output from the output end;

[0108] Step S3 includes: obtaining the spectral transmittance function of the gas to be detected based on the maximum and minimum values ​​of all actual light intensities obtained during each data acquisition process.

[0109] In application, based on the maximum and minimum value method of direct absorption, the expressions for the maximum and minimum values ​​among all actual light intensities in step S1 are as follows:

[0110] Where S(λ) represents the spectral transmittance function, Out(λ,δ) represents the actual light intensity, max(Out(λ,δ)) represents the maximum value among all actual light intensities, min(Out(λ,δ)) represents the minimum value among all actual light intensities, I(λ,δ) represents the theoretical light intensity of the interference beam, max(I(λ,δ)) represents the maximum value among all theoretical light intensities, min(I(λ,δ)) represents the minimum value among all theoretical light intensities, ε represents the amplitude of the interference beam and is a small quantity, and L represents the optical path difference between the interference beam and the probe beam.

[0111] In application, by simultaneously solving Equations 1 and 2, (1+2ε) and (1-2ε) can be eliminated, yielding the following expression for the spectral transmittance function:

[0112] In application, a gas absorption data detection method based on the maximum and minimum value method of direct absorption is used. The wavelength of the detection beam is set to a constant wavelength during each data acquisition process. When the M sub-reflectors move back and forth periodically along the Z-axis, the sum of the position changes in the Z-axis direction is limited to 0.5 to 10 times the wavelength of the detection beam. It is not required that the sum of the position changes be an integer multiple of 0.5 times the wavelength of the detection beam. The control precision requirements of the drive mechanism are low. The spectral transmittance function of the gas to be detected is obtained directly from the maximum and minimum values ​​of all actual light intensities obtained in each data acquisition process. The algorithm is simple, the computation is small, and the detection efficiency can be effectively improved.

[0113] In one embodiment, the gas absorption data detection method is based on the averaging method of direct absorption, and the wavelength of the detection beam is constant during each data acquisition process;

[0114] Step S1 includes: during each data acquisition process in the detection process, controlling the drive mechanism to drive the M sub-mirrors of the optical multi-pass cell to periodically reciprocate along the Z-axis direction, so that the sum of the position changes of the M sub-mirrors in the Z-axis direction varies at N different positions within the range of 0.25 to 10 times the wavelength of the detection beam, i.e., δ μ =(μ-1)δ0, μ = 1, 2, 3, ..., N, δ0 > 0 and δ0 is a constant, N ≥ 2; δ μ δ represents the sum of the μ-th positional change value among the sums of N distinct positional change values. N This represents the maximum value among the sums of N different positional changes.

[0115] Step S2 includes: during the periodic reciprocating motion of the M sub-mirrors along the Z-axis for one or more cycles, obtaining the actual light intensity of the interference beam output from the output end;

[0116] Step S3 includes: obtaining the spectral transmittance function of the gas to be detected based on the average value of the actual light intensity at the sum of N different position changes obtained during each data acquisition process.

[0117] In application, based on the averaging method of direct absorption, the expression for the average value of the actual light intensity at the sum of the changes at N different locations in step S1 is as follows:

[0118] Substituting formula 4 into formula 3, we get:

[0119] Mathematically, it can be proven that when the maximum value δ of the sum of the changes at N different positions is... N The number of position samples N and the sum of the μth position change value among the sums of N different position change values ​​δ μ When formulas 6 to 8 are satisfied, the summation of the cosine function in formula 5 is zero, and the 1 in the expression is accumulated N times, resulting in a summation of N. Therefore, formula 9 can be obtained: N = mk (Formula 7) ave(Out(λ,δ))=S(λ)·1=S(λ)(Formula 9)

[0120] From Equations 5 and 9, the expression for the spectral transmittance function can be obtained as follows:

[0121] Where Out(λ,δ) μ ) represents the actual light intensity at the sum of the μ-th position change values, ave(Out(λ,δ)) represents the average actual light intensity at the sum of the N different position change values, and I(λ,δ) μ) represents the sum of the positional changes of the M sub-mirrors along the Z-axis, δ. μ The theoretical light intensity of the time-interference beam.

[0122] This application embodiment implements a gas absorption data detection method based on the averaging method of direct absorption. The wavelength of the detection beam is set to a constant wavelength during each data acquisition process. When the M sub-reflectors periodically move back and forth along the Z-axis, the sum of the N position changes along the Z-axis is set to a linear change, all within the range of 0.25 to 10 times the wavelength of the detection beam. Then, based on the average value of the actual light intensity at the sum of the N different position changes obtained during each data acquisition process, the spectral transmittance function of the gas to be detected is obtained, which can effectively improve the accuracy of detection efficiency.

[0123] In one embodiment, the gas absorption data detection method is based on the averaging method of the harmonic method, and the wavelength of the detection beam varies within a preset wavelength modulation range during each data acquisition process.

[0124] Step S1 includes: during each data acquisition process in the detection process, controlling the drive mechanism to drive the M sub-mirrors of the optical multi-pass cell to periodically reciprocate along the Z-axis direction, so that the sum of the position changes of the M sub-mirrors in the Z-axis direction varies at N different positions within the range of 0.25 to 10 times the wavelength of the detection beam, i.e., δ μ =(μ-1)δ0, μ = 1, 2, 3, ..., N, δ0 > 0 and δ0 is a constant, N ≥ 2; δ μ δ represents the sum of the μth position change value among the sums of the N different position change values. N This represents the maximum value among the sums of the N different positional changes;

[0125] Step S2 includes: during the periodic reciprocating motion of the M sub-mirrors along the Z-axis for one or more cycles, obtaining the actual light intensity of the interference beam output from the output end;

[0126] Step S3 includes:

[0127] Based on the actual light intensity at the sum of N different positional change values ​​obtained during each data acquisition process, obtain the corresponding harmonic spectral function at the sum of N different positional change values.

[0128] The spectral transmittance function of the gas to be detected is obtained by taking the average value of the harmonic spectral function at the sum of the N different positional variation values. That is, by performing an inverse Fourier transform on the average value of the harmonic spectral function at the sum of the N different positional variation values, the spectral transmittance function of the gas to be detected is obtained.

[0129] In application, based on the harmonic averaging method, the expression for the average value of the harmonic spectral function at the sum of the N different positional changes in step S3 is as follows:

[0130] By interchanging the summation and integration signs in Formula 10, we get:

[0131] By analyzing the summation part of Equation 11, we can see that the wavelength modulation width αφ is much smaller than the wavelength λ, therefore:

[0132] Mathematically, it can be proven that when the maximum value δ of the sum of the changes at N different positions is... N The number of position samples N and the sum of the μth position change value among the sums of N different position change values ​​δ μ When formulas 13 to 15 are satisfied, the summation of the cosine function in formula 12 is zero, and the 1 in the expression is accumulated N times, resulting in a summation of N, which leads to formula 16: N = mk (Formula 14)

[0133] By performing an inverse Fourier transform on Equation 16, we can obtain S(λ+αφ), which eliminates the interference effect. Equation 16 is the harmonic spectral line with the interference effect eliminated.

[0134] Where λ represents the center wavelength of the probe beam, H n (λ,δ μ H represents the harmonic spectral function at the sum of the μ-th positional changes. n (λ) represents the average value of the harmonic spectral function at the sum of N different positional variations, S(λ+αφ) represents the spectral transmittance function, α represents the wavelength modulation coefficient of the probe beam, φ represents the wavelength modulation parameter of the light source device (e.g., a laser) used to emit the probe beam, and n represents the harmonic order. This represents the phase shift corresponding to the nth harmonic.

[0135] In applications, the averaging method based on harmonic methods has two equivalent signal processing approaches, as follows:

[0136] The first type: in each δ μ At this point, a set of harmonic spectral functions is obtained. Then, the average value of the N sets of harmonic spectral functions is obtained, as shown in the following expression:

[0137] The second method: at each center wavelength λ, for each δ μScan the wavelength αφ within the wavelength modulation range to obtain the theoretical light intensity of the interference beam. Then, calculate the average value of the spectral transmittance function ave(S(λ+αφ)) for N sets of wavelength data. Finally, solve for the harmonic spectral function according to the following expression:

[0138] This application embodiment implements a gas absorption data detection method based on the harmonic averaging method. During each data acquisition process, the wavelength of the detection beam is set to vary within a preset wavelength modulation range. When M sub-reflectors periodically reciprocate along the Z-axis, the sum of N positional changes along the Z-axis is set to change linearly and all within 0.25 to 10 times the wavelength of the detection beam. Then, based on the actual light intensity at the sum of the N different positional changes obtained during each data acquisition process, the corresponding harmonic spectral function at the sum of the N different positional changes is obtained. Finally, based on the average value of the harmonic spectral functions at the sum of the N different positional changes, the spectral transmittance function of the gas to be detected is obtained, which can effectively improve the accuracy of the detection efficiency.

[0139] This invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, can implement the steps described in the above-described gas absorption data detection method embodiments.

[0140] This invention provides a computer program product that, when run on a terminal device, enables the terminal device to implement the steps described in the above-described gas absorption data detection method embodiment.

[0141] In applications, computer-readable media can include at least: any entity or device capable of carrying computer program code to a terminal device, recording media, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media. Examples include USB flash drives, portable hard drives, magnetic disks, or optical disks. In the above embodiments, the descriptions of each embodiment have different focuses; parts not described in detail in a particular embodiment can be referred to in the relevant descriptions of other embodiments.

[0142] Those skilled in the art will recognize that the devices described in connection with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0143] In the embodiments provided in this application, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods, such as multiple devices being combined or integrated.

[0144] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. An optical multi-pass cell system, characterized in that, include: An optical multipass cell, including an input end and an output end; as well as A drive mechanism is used to drive the M sub-mirrors of the optical multipass cell to periodically reciprocate along the Z-axis direction during each data acquisition process in the gas absorption data detection process. The Z-axis direction is parallel to the optical axis of the optical multipass cell. Where M≥1, the detection process is as follows: when the gas to be detected is filled into the optical multipass cell, the detection beam is input from the input end, and after multiple reflections in the optical multipass cell, an interference beam is formed and output from the output end. During the entire detection process, the wavelength of the detection beam changes within a preset wavelength range. During each data acquisition process, the wavelength of the detection beam is constant or changes within a preset wavelength modulation range.

2. The optical multi-pass cell system as described in claim 1, characterized in that, The optical multi-pass cell includes: The input terminal is used to input the detection beam; The output end is used to output an interference beam; The principal concave mirror; and Two sub-reflectors, each a concave reflector, are provided. The reflecting surfaces of the main concave reflector and the sub-reflectors are opposite to each other and spaced apart to form a reflecting cavity. The optical axis of the reflecting cavity is perpendicular to the focal plane of the main concave reflector. The input terminal is disposed on the main concave reflector, and the output terminal is disposed on the main concave reflector or any of the sub-reflectors.

3. The optical multi-pass cell system as described in claim 1, characterized in that, The optical multi-pass cell includes: The input terminal is used to input the detection beam; The output end is used to output an interference beam; Concave mirror; A primary plane mirror, wherein the reflecting surfaces of the primary concave mirror and the primary plane mirror are opposite to and spaced apart to form a reflecting cavity, and the optical axis of the reflecting cavity is perpendicular to the focal plane of the primary concave mirror; and N sub-mirrors are disposed on the main plane mirror, and the reflecting surfaces of the N sub-mirrors are arranged facing the main concave mirror. Wherein, N≥M, the input terminal is disposed on the main concave reflector or the main planar reflector, and the output terminal is disposed on the main concave reflector, the main planar reflector or any of the sub-reflectors.

4. The optical multi-pass cell system as described in claim 3, characterized in that, N=1, the sub-reflector is a plane reflector with an area smaller than the main plane reflector; The tilt angle between the normal of the sub-reflector and the normal of the main plane reflector is θ1, and the tilt angle θ1 is not zero; The drive mechanism is used to drive the sub-reflector to move.

5. The optical multi-pass cell system as described in claim 3, characterized in that, N=2, and the N sub-mirrors include a first sub-mirror and a second sub-mirror; Both the first sub-reflector and the second sub-reflector are planar reflectors with an area smaller than that of the main plane reflector. The tilt angle between the normal of the first sub-reflector and the normal of the main plane reflector is θ1 and the tilt angle θ1 is not zero. The normal of the second sub-reflector is parallel to the normal of the main plane reflector. The second sub-reflector and the first sub-reflector are symmetrically arranged and separated about the origin, which is the intersection of the optical axis on the focal plane. The drive mechanism is used to drive the second sub-reflector to move.

6. The optical multi-pass cell system as described in claim 3, characterized in that, N=2, and the N sub-mirrors include a first sub-mirror and a second sub-mirror; The first sub - mirror and the second sub - mirror are both plane mirrors with areas smaller than that of the main plane mirror. The inclination angle between the normal of the first sub - mirror and the normal of the main plane mirror is θ1 and the inclination angle θ1 is non - zero; The normal of the second sub - mirror is parallel to the normal of the main plane mirror. The second sub - mirror and the first sub - mirror are symmetric about the origin and are adjacent to each other. The origin is the intersection point of the optical axis on the focal plane; The driving mechanism is used to drive the first sub - mirror and the second sub - mirror to move simultaneously.

7. The optical multi-pass cell system as described in claim 3, characterized in that, N = 2, and the N sub - mirrors include the first sub - mirror and the second sub - mirror; The first sub - mirror and the second sub - mirror are both plane mirrors with areas smaller than that of the main plane mirror. The inclination angle between the normal of the first sub - mirror and the normal of the main plane mirror is θ1 and the inclination angle θ1 is non - zero; The inclination angle between the normal of the second sub - mirror and the normal of the main plane mirror is θ2 and the inclination angle θ2 is non - zero. The second sub - mirror and the first sub - mirror are symmetric about the origin and are adjacent to each other. The origin is the intersection point of the optical axis on the focal plane; The driving mechanism is used to drive the first sub - mirror and the second sub - mirror to move simultaneously.

8. The optical multi-pass cell system as described in claim 1, characterized in that, The optical multi - pass cell includes: The input end, which is used to input the probe beam; The output end, which is used to output the interference beam; The main concave mirror, with a focal length of f, a radius of curvature of R and having aberration; The main plane mirror, the distance from the reflecting surface of the main plane mirror to the optical center of the main concave mirror is L1=(1 + x1)f, - 1 < x1 < 1; and The sub - mirror, which is a concave mirror with a focal length of f0, a radius of curvature of R0 and is arranged on the main plane mirror. The area of the positive projection of the reflecting surface of the sub - mirror on the reflecting surface of the main plane mirror is smaller than the area of the reflecting surface of the main plane mirror. The distance from the optical center of the sub - mirror to the optical center of the main concave mirror is L2=(1 + x2)f, R0 = mR, - 1 < x2 < 1, x1 and x2 are not both 0, m > 0; Wherein, the input end is arranged on the main concave mirror or the main plane mirror, the output end is arranged on the main concave mirror, the main plane mirror or the sub - mirror. The reflecting surface of the main concave mirror is opposite and spaced from the reflecting surfaces of the main plane mirror and the sub - mirror to form a reflection cavity. The optical axis of the reflection cavity is perpendicular to the reflecting surface of the plane mirror and passes through the optical center and the focus of the main concave mirror.

9. The optical multi-pass cell system according to any one of claims 1 to 8, characterized in that, The Z - axis direction includes the positive Z - axis direction and the negative Z - axis direction which are parallel and opposite; The position change value of the sub - mirror when moving along the positive Z - axis direction is positive; The position change value of the sub - mirror when moving along the negative Z - axis direction is negative; When the M sub-mirrors periodically reciprocate along the Z-axis direction, Wherein, δ represents the sum of the position change values of the M sub - mirrors in the Z - axis direction, and λ represents the wavelength of the probe beam.

10. A method for detecting gas absorption data, characterized in that, Based on the optical multi-pass cell system of claim 9, the gas absorption data detection method includes: During each data acquisition process of the detection process, the drive mechanism is controlled to drive the M sub-mirrors of the optical multi-pass cell to periodically reciprocate along the Z-axis direction; Obtain the actual light intensity of the interference beam output from the output end; Based on the actual light intensity, obtain the spectral transmittance function of the gas to be detected; Based on the spectral transmittance function, noise-smoothed gas absorption data of the gas to be detected are obtained.

11. The gas absorption data detection method as described in claim 10, characterized in that, The method is based on the maximum and minimum values ​​of direct absorption, and the wavelength of the probe beam remains constant during each data acquisition process. Based on the actual light intensity, the spectral transmittance function of the gas to be detected is obtained, including: Based on the maximum and minimum values ​​of all actual light intensities obtained during each data acquisition process, the spectral transmittance function of the gas to be detected is obtained. in, 12. The gas absorption data detection method as described in claim 11, characterized in that, The expression for the spectral transmittance function is: Where S(λ) represents the spectral transmittance function, Out(λ,δ) represents the actual light intensity, max(Out(λ,δ)) represents the maximum value among all actual light intensities, and min(Out(λ,δ)) represents the minimum value among all actual light intensities.

13. The gas absorption data detection method as described in claim 10, characterized in that, The average value method based on direct absorption is used, and the wavelength of the probe beam remains constant during each data acquisition process; Based on the actual light intensity, the spectral transmittance function of the gas to be detected is obtained, including: The spectral transmittance function of the gas to be detected is obtained by summing the actual light intensity at the sum of the N different position changes obtained during each data acquisition process. among them,d μ =(μ-1)δ0, μ = 1, 2, 3, ..., N, δ0 > 0 and δ0 is a constant, N ≥ 2; δ μ δ represents the sum of the μth position change value among the sums of the N different position change values. N This represents the maximum value among the sum of the N different positional changes.

14. The gas absorption data detection method as described in claim 13, characterized in that, The expression for the spectral transmittance function is: in, k=1,2,3,…, m=2,3,4,…; N=mk; S(λ) represents the spectral transmittance function, Out(λ,δ) μ ) represents the actual light intensity at the sum of the μ-th position change values.

15. The gas absorption data detection method as described in claim 10, characterized in that, The average value method based on harmonic method is used, and the wavelength of the probe beam changes within a preset wavelength modulation range during each data acquisition process; The step of obtaining the spectral transmittance function of the gas to be detected based on the actual light intensity includes: Based on the actual light intensity at the sum of N different positional change values ​​obtained during each data acquisition process, obtain the corresponding harmonic spectral function at the sum of N different positional change values. The spectral transmittance function of the gas to be detected is obtained by taking the average value of the harmonic spectral function at the sum of the N different positional variation values. Wherein, the preset wavelength modulation range is within the preset wavelength range, δ μ =(μ-1)δ0, μ = 1, 2, 3, ..., N, δ0 > 0 and δ0 is a constant, N ≥ 2; δ μ δ represents the sum of the μth position change value among the sums of the N different position change values. N This represents the maximum value among the sum of the N different positional changes.

16. The gas absorption data detection method as described in claim 15, characterized in that, The expression for the average value of the harmonic spectral function at the sum of the N different positional variations is: in, k=1,2,3,…, m=2,3,4,…; N=mk; H n (λ) represents the average value of the harmonic spectral function at the sum of the N different positional variations, S(λ+αφ) represents the spectral transmittance function, α represents the wavelength modulation coefficient of the probe beam, φ represents the wavelength modulation parameter of the light source device used to emit the probe beam, and n represents the harmonic order. This represents the phase shift corresponding to the nth harmonic.

17. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the gas absorption data detection method as described in any one of claims 10 to 16.

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