Quantum cascade laser automatic calibration and gas concentration inversion device and method

Abstract

The invention discloses a quantum cascade laser automatic calibration and gas concentration inversion device and method, and the device comprises a supporting structure which comprises a supporting plate, and the lower end of the supporting plate is fixedly connected with a plurality of supporting legs; the calibration inversion structure comprises a laser fixedly connected to the upper end of the supporting plate, a reflector is arranged on the supporting plate on the front side of the output end of the laser, a vertical circular plate is fixedly connected to the center of the upper end of the supporting plate, a stepping motor is fixedly connected to the side wall of the circular plate, and a driving shaft of the stepping motor is fixedly sleeved with a filter wheel; a plurality of gas filtering air chambers and a Ge etalon are uniformly distributed on the side wall of the light filtering wheel; and a light beam of the laser passes through the Ge etalon or the gas filtering air chambers on the light filtering wheel through the reflecting mirror and passes out. According to the invention, the spectrum in the time domain can be recorded by adopting the high-bandwidth mid-infrared MCT detector and the high-speed data acquisition device, and the information of the related spectrum in the frequency domain can be obtained by combining with the high-resolution etalon.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor lasers, and in particular to a quantum cascade laser automatic calibration and gas concentration inversion device and method. Background Art

[0002] NO2 is an important atmospheric pollutant, a harmful gas released by automobile exhaust, garbage burning, smoking, etc. When the concentration of NO2 in the atmosphere increases, it can have direct or indirect effects on the environment in the following aspects: free radical reactions occur in the stratosphere, destroying stratospheric ozone; nitric acid is generated at the bottom of the stratosphere, entering the clouds to form acidic precipitation; after being transmitted through the atmosphere, it enters the troposphere and increases the concentration of tropospheric ozone through photochemical reactions, making it a greenhouse gas. Therefore, monitoring the sources of NO2 in the atmosphere in order to implement effective control and management is of great significance to the biosphere.

[0003] At present, there are mainly chemical and optical methods for detecting NO2 gas in the atmosphere. The chemical methods mainly include chemiluminescence and electrochemical methods. Since chemical methods usually require sample pretreatment, the process is complicated and time-consuming, and is easily interfered by other substances, and may also cause artificial products, it is particularly unsuitable for real-time continuous measurement, making optical methods an increasingly popular measurement technology. In particular, the use of tunable infrared laser absorption spectroscopy technology to measure NO2 gas in the atmosphere can not only overcome the sampling and pretreatment problems in chemical methods, but also completely avoid interference from other gases, and achieve highly sensitive detection of the gas to be measured in an ultra-short time.

[0004] Frequency calibration is of great significance in the fields of precision measurement, optical communication, laser technology, etc. The current frequency calibration technology is mainly carried out using FP (Fabry-Perot) interferometer. FP interferometer has good frequency discrimination ability and high-precision measurement performance, so it is widely used in many precision measurement fields. However, the existing frequency calibration technology based on FP etalon still has some problems. First, traditional FP etalons usually require precise manufacturing processes and complex debugging processes, resulting in high costs. Secondly, the existing FP etalon is easily affected by factors such as temperature changes and mechanical vibrations after long-term use, resulting in frequency drift and instability. In addition, the FP etalon frequency calibration method in the prior art may require complex data processing and calculations, and there is a certain degree of operational complexity and inconvenience. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the problems existing in the above-mentioned existing quantum cascade laser automatic calibration and gas concentration inversion devices and methods, the present invention is proposed.

[0007] Therefore, the purpose of the present invention is to provide a quantum cascade laser automatic calibration and gas concentration inversion device, which can record the spectrum in the time domain by adopting a high-bandwidth mid-infrared MCT detector and a high-speed data acquisition device, and combined with a high-resolution standard tool, can obtain information about the spectrum in the frequency domain.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: a quantum cascade laser automatic calibration and gas concentration inversion device, comprising:

[0009] A support structure, comprising a support plate, a lower end of which is fixedly connected to a plurality of support legs;

[0010] A calibration inversion structure comprises a laser fixedly connected to the upper end of a support plate, a reflector is arranged on the support plate in front of the output end of the laser, a vertical circular plate is fixedly connected to the center of the upper end of the support plate, a stepper motor is fixedly connected to the side wall of the circular plate, and a filter wheel is fixedly sleeved on the driving shaft of the stepper motor, a plurality of gas filter chambers and a Ge standard tool are evenly arranged on the side wall of the filter wheel, the light beam of the laser passes through the Ge standard tool or the gas filter chamber on the filter wheel through the reflector and passes out, an off-axis parabolic mirror opposite to the reflector is fixedly connected to the upper end of the support plate, a photodetector is fixedly connected to the support plate on one side of the off-axis parabolic mirror, and the light beam is transmitted to the photodetector through the off-axis parabolic mirror.

[0011] As a preferred solution of the quantum cascade laser automatic calibration and gas concentration inversion device of the present invention, the plurality of gas filter chambers are respectively filled with N2, NO, CO2, NO2, C2H2, and CH4.

[0012] As a preferred solution of the quantum cascade laser automatic calibration and gas concentration inversion device described in the present invention, the laser adopts a quantum cascade laser, and the integrated Ge standard tool and the gas filter chamber are integrated on a filter wheel, and the automatic calibration of the quantum cascade laser is realized by stepper motor control.

[0013] As a preferred solution of the quantum cascade laser automatic calibration and gas concentration inversion device of the present invention, the quantum cascade laser is connected to an external host computer and synchronized with the host computer acquisition card to perform data acquisition. The photoelectric detector adopts a high-bandwidth mid-infrared MCT detector, and the photoelectric detector is connected to an external high-speed data acquisition device to record the spectrum in the time domain. Combined with the standard tool, information about the spectrum in the frequency domain can be obtained.

[0014] As a preferred solution of the quantum cascade laser automatic calibration and gas concentration inversion device described in the present invention, wherein: after the emission current pulse, the continuous power of the spectrum in the time domain gradually decreases with time and reaches a minimum value at the end; the thermal dissipation of the laser increases the heat sink temperature of the laser, and the laser threshold will also increase with the increase of the heat sink temperature, that is, while the laser negative chirps, the required threshold current also becomes higher and higher.

[0015] A quantum cascade laser automatic calibration and gas concentration inversion method, wherein: the automatic time domain to frequency domain calibration in the quantum cascade laser automatic calibration and gas concentration inversion device inversion method comprises the following steps:

[0016] Step 1: Control the stepper motor to rotate, place the Ge etalon in the optical path, control the quantum cascade laser to emit light, and synchronize the host computer acquisition card to collect data to obtain a stable Etalon interference peak signal;

[0017] Step 2: Use the acquisition card to collect the interference signal output by the standard tool, average it multiple times, and then use the host computer to automatically find the peak to achieve relative frequency calibration;

[0018] Step 3: Data processing: The time value corresponding to each interference peak is obtained by the interference signal peak finding method. The time point of the interference peak is used as the horizontal coordinate, and the frequency interval between peaks is the free spectrum range (FSR) of the etalon. The above data points are fitted to the third power to obtain the fitting equation.

[0019] Step 4: Transfer the gas filter chamber into the optical path, obtain the time value corresponding to the corresponding gas absorption peak, compare it with the theoretical wave number position corresponding to the absorption peak obtained by HITRAN, and make a one-to-one correspondence between the two to know the frequency domain position corresponding to the gas absorption peak;

[0020] Step 5: Change the time axis of the long pulse spectrum signal into the frequency domain axis expressed in wave numbers. Time-frequency conversion: convert the data sequence number into time, and then into wave numbers.

[0021] As a preferred solution of the quantum cascade laser automatic calibration and gas concentration inversion device of the present invention, the fitting equation in step three is:

[0022] y=Intercept+B1*x+B2*x 2 +B3*x 3

[0023] Among them, Intercept is a function, which refers to the distance from the intersection of the function graph and the coordinate axis to the origin;

[0024] B1, B2, B3 are cubic function coefficients; x, y are the positions of the peak and trough respectively.

[0025] As a preferred solution of the quantum cascade laser automatic calibration and gas concentration inversion device of the present invention, the value of B1 is 0.48327±0.00504; the value of B2 is -0.00137±3.0727E-5; and the value of B3 is 1.6479E-6±5.92536E-8.

[0026] As a preferred solution of the method for automatic calibration of quantum cascade laser and inversion of gas concentration of the present invention, the following two formulas are used in step 5:

[0027] t=x÷N

[0028] v=a×t^3+b×t^2+c×t+d

[0029] Among them, x is the data sequence number, N is the detector scanning frequency, t is the time, a, b, c, d are the polynomial coefficients, and v is the wave number.

[0030] As a preferred solution of the method for automatic calibration of quantum cascade laser and inversion of gas concentration of the present invention, the specific operation of inversion of gas concentration of quantum cascade laser in the method for automatic calibration of quantum cascade laser and inversion of gas concentration includes the following steps:

[0031] S1. First, take the baseline area of ​​the transmission spectrum, use a quadratic polynomial to obtain the baseline, convert the transmission spectrum into an absorbance spectrum, and obtain the absorbance spectrum of the substance;

[0032] S2. Perform multiple sets of Voigt line parameter fitting modeling on the absorbance spectra of standard substances to obtain a standard substance spectrum library, in which the intensity and line width will change due to the influence of temperature and pressure, in preparation for subsequent concentration inversion;

[0033] S3. Using the least squares method, by comparing the absorbance data of the standard substance Voigt model, the concentration of the gas substance in the measured data is obtained, thereby realizing gas concentration inversion.

[0034] Beneficial effects of the present invention: The present invention uses a method of comparing a standard spectrum database to calibrate the frequency of the gas absorption peak in the time domain signal, thereby converting the time domain signal in the entire time range into a frequency domain signal. The present invention integrates an integrated Ge standard tool and a gas filter chamber (GFC) on a filter wheel, and realizes the automatic calibration of a quantum cascade laser (QCL) through stepper motor control. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0036] Figure 1 It is a schematic diagram of the overall Etalon frequency domain calibration structure of the quantum cascade laser automatic calibration and gas concentration inversion device and method of the present invention;

[0037] Figure 2 It is a side structural schematic diagram of the quantum cascade laser automatic calibration and gas concentration inversion device and method of the present invention;

[0038] Figure 3 It is a schematic diagram of the excitation pulse spectrum and gas absorption shape of the quantum cascade laser automatic calibration and gas concentration inversion device and method of the present invention;

[0039] Figure 4 A schematic diagram of obtaining a stable Etalon signal and relative frequency calibration for the automatic calibration of a quantum cascade laser and a gas concentration inversion device and method of the present invention;

[0040] Figure 5 A schematic diagram of the functional relationship between the free spectrum range and the spectrum acquisition time of the quantum cascade laser automatic calibration and gas concentration inversion device and method of the present invention;

[0041] Figure 6 It is a schematic diagram of the gas absorbance curve in the frequency domain of the laser scanning band of the quantum cascade laser automatic calibration and gas concentration inversion device and method of the present invention;

[0042] Figure 7 The figure is a schematic diagram for comparing peak shapes and determining the central frequency of characteristic absorption peaks of the quantum cascade laser automatic calibration and gas concentration inversion device and method of the present invention. DETAILED DESCRIPTION

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0044] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0045] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0046] Secondly, the present invention is described in detail with reference to the schematic diagram. When describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0047] Reference Figure 1-Figure 7 , provides a quantum cascade laser automatic calibration and gas concentration inversion device, including:

[0048] A support structure 100 and a calibration inversion structure 200, wherein the support structure 100 comprises a support plate 101, and a plurality of support legs 102 are fixedly connected to the lower end of the support plate 101;

[0049] The calibration inversion structure 200 includes a laser 201 fixedly connected to the upper end of the support plate 101, a reflector 202 is arranged on the support plate 101 in front of the output end of the laser 201, a vertical circular plate 203 is fixedly connected to the center of the upper end of the support plate 101, a stepper motor 204 is fixedly connected to the side wall of the circular plate 203, and a filter wheel 205 is fixedly sleeved on the driving shaft of the stepper motor 204, and a plurality of gas filters are evenly arranged on the side wall of the filter wheel 205. The filter chamber 206 and a Ge etalon 207, the light beam of the laser 201 passes through the Ge etalon 207 or the gas filter chamber 206 on the filter wheel 205 through the reflector 202 and passes out, the upper end of the support plate 101 is fixedly connected with an off-axis parabolic mirror 208 opposite to the reflector 202, and a photodetector 209 is fixedly connected to the support plate 101 on one side of the off-axis parabolic mirror 208, and the light beam is transmitted to the photodetector 209 through the off-axis parabolic mirror 208.

[0050] Among them, multiple gas filter chambers 206 are respectively filled with N2, NO, CO2, NO2, C2H2, and CH4; the laser 201 adopts a quantum cascade laser, and the integrated Ge standard tool 207 and the gas filter chamber 206 are integrated on a filter wheel 205, which is controlled by a stepper motor 204 to realize the automatic calibration of the quantum cascade laser.

[0051] Among them, the quantum cascade laser is connected to an external host computer and synchronized with the host computer acquisition card for data acquisition. The photodetector adopts a high-bandwidth mid-infrared MCT detector, and the photodetector is connected to an external high-speed data acquisition device to record the spectrum in the time domain. Combined with the standard tool, it can obtain information about the spectrum in the frequency domain.

[0052] Furthermore, Figure 3 The variation of the excited light intensity signal with time. The successful recording of QCL light pulses is due to the fast time response of the detector and the high-speed digitization process of the digital acquisition card. The baseline before and after the rising and falling edges of the light pulse is the voltage response of the detector when there is no laser. As can be seen from the figure, after the emission current pulse, the continuous power of the spectrum in the time domain gradually decreases with time and reaches a minimum value at the end. This is because the thermal dissipation of the laser increases the heat sink temperature of the laser, and the laser threshold will also increase with the increase of the heat sink temperature, that is, while the laser is negatively chirped, the required threshold current is also getting higher and higher. Since the laser current is constant, the corresponding light output energy is getting lower and lower.

[0053] The automatic calibration of quantum cascade laser and the automatic time-domain to frequency-domain conversion in the gas concentration inversion method process include the following steps:

[0054] Step 1: Control the stepper motor 204 to rotate, place the Ge etalon 207 in the optical path, control the quantum cascade laser to emit light, and synchronize the host computer acquisition card to collect data to obtain a stable Etalon interference peak signal;

[0055] Step 2: Use the acquisition card to collect the interference signal output by the standard tool, average it multiple times, and then use the host computer to automatically find the peak to achieve relative frequency calibration;

[0056] Step 3: Data processing: The time value corresponding to each interference peak is obtained by the interference signal peak finding method. The time point of the interference peak is used as the horizontal coordinate, and the frequency interval between peaks is the free spectrum range (FSR) of the etalon. The above data points are fitted to the third power to obtain the fitting equation.

[0057] Step 4: Turn the gas filter chamber 206 into the optical path, obtain the time value corresponding to the corresponding gas absorption peak, compare it with the theoretical wave number position corresponding to the absorption peak obtained by HITRAN, and make a one-to-one correspondence between the two to know the frequency domain position corresponding to the gas absorption peak;

[0058] Step 5: Change the time axis of the long pulse spectrum signal into the frequency domain axis expressed in wave numbers. Time-frequency conversion: convert the data sequence number into time, and then into wave numbers.

[0059] Furthermore, the fitting equation in step three is:

[0060] y=Intercept+B1*x+B2*x 2 +B3*x 3

[0061] Among them, Intercept is a function, which refers to the distance from the intersection of the function graph and the coordinate axis to the origin;

[0062] B1, B2, B3 are cubic function coefficients; x, y are the positions of the peak and trough respectively.

[0063] Specifically, refer to Figure 4 , the value of B1 is 0.48327±0.00504; the value of B2 is -0.00137±3.0727E-5; the value of B3 is 1.6479E-6±5.92536E-8.

[0064] Among them, the following two formulas are used in step 5:

[0065] t=x÷N

[0066] v=a×t^3+b×t^2+c×t+d

[0067] Among them, x is the data sequence number, N is the detector scanning frequency, t is the time, a, b, c, d are the polynomial coefficients, and v is the wave number.

[0068] Specifically, the specific operation of quantum cascade laser gas concentration inversion in the quantum cascade laser automatic calibration and gas concentration inversion method includes the following steps:

[0069] S1. First, take the baseline area of ​​the transmission spectrum, use a quadratic polynomial to obtain the baseline, convert the transmission spectrum into an absorbance spectrum, and obtain the absorbance spectrum of the substance;

[0070] S2. Perform multiple sets of Voigt line parameter fitting modeling on the absorbance spectra of standard substances to obtain a standard substance spectrum library, in which the intensity and line width will change due to the influence of temperature and pressure, in preparation for subsequent concentration inversion.

[0071] S3. Using the least squares method, by comparing the absorbance data of the standard substance Voigt model, the concentration of the gas substance in the measured data is obtained, thereby realizing gas concentration inversion.

[0072] Among them, the Voigt model is an existing spectrum fitting method and will not be described in detail here.

[0073] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A quantum cascade laser automatic calibration and gas concentration inversion device, characterized in that: include: A support structure (100), comprising a support plate (101), wherein a plurality of support legs (102) are fixedly connected to the lower end of the support plate (101); A calibration inversion structure (200) comprises a laser (201) fixedly connected to the upper end of a support plate (101), a reflector (202) being arranged on the support plate (101) in front of the output end of the laser (201), a vertical circular plate (203) being fixedly connected to the center of the upper end of the support plate (101), a stepper motor (204) being fixedly connected to the side wall of the circular plate (203), a filter wheel (205) being fixedly sleeved on the driving shaft of the stepper motor (204), and a plurality of gas filter wheels (205) being evenly arranged on the side wall of the filter wheel (205). The invention relates to a gas chamber (206) and a Ge etalon (207), wherein the light beam of the laser (201) passes through the Ge etalon (207) on the filter wheel (205) or the gas filter gas chamber (206) through the reflector (202) and then passes out, and the upper end of the support plate (101) is fixedly connected with an off-axis parabolic mirror (208) opposite to the reflector (202), and a photoelectric detector (209) is fixedly connected to the support plate (101) on one side of the off-axis parabolic mirror (208), and the light beam is transmitted to the photoelectric detector (209) through the off-axis parabolic mirror (208).

2. The quantum cascade laser automatic calibration and gas concentration inversion device according to claim 1, characterized in that: The plurality of gas filter chambers (206) are respectively filled with N2, NO, CO2, NO2, C2H2, and CH4.

3. The quantum cascade laser automatic calibration and gas concentration inversion device according to claim 2, characterized in that: The laser (201) adopts a quantum cascade laser, and an integrated Ge standard tool (207) and a gas filter chamber (206) are integrated on a filter wheel (205), and the automatic calibration of the quantum cascade laser is realized through the control of a stepping motor (204).

4. The quantum cascade laser automatic calibration and gas concentration inversion device according to claim 3, characterized in that: The quantum cascade laser is connected to an external host computer and synchronized with the host computer acquisition card to perform data acquisition. The photodetector adopts a high-bandwidth mid-infrared MCT detector, and the photodetector is connected to an external high-speed data acquisition device to record the spectrum in the time domain. Combined with the standard tool, information about the spectrum in the frequency domain can be obtained.

5. The quantum cascade laser automatic calibration and gas concentration inversion device according to claim 1, characterized in that: After the emission current pulse, the continuous power of the spectrum in the time domain gradually decreases with time and reaches a minimum value at the end; the heat dissipation of the laser (201) increases the heat sink temperature of the laser, and the laser threshold also increases with the increase of the heat sink temperature, that is, while the laser negative chirps, the required threshold current also becomes higher and higher.

6. A quantum cascade laser automatic calibration and gas concentration inversion method, characterized in that quantum The automatic calibration of cascade lasers and the automatic time-domain to frequency-domain calibration in gas concentration inversion include the following steps: Step 1: Control the stepper motor (204) to rotate, place the Ge etalon (207) in the optical path, control the quantum cascade laser to emit light, and synchronize the host computer acquisition card to perform data acquisition to obtain a stable Etalon interference peak signal; Step 2: Use the acquisition card to collect the interference signal output by the standard tool, average it multiple times, and then use the host computer to automatically find the peak to achieve relative frequency calibration; Step 3: Data processing: The time value corresponding to each interference peak is obtained by the interference signal peak finding method. The time point of the interference peak is used as the horizontal coordinate, and the frequency interval between peaks is the free spectrum range (FSR) of the etalon. The above data points are fitted to the third power to obtain the fitting equation. Step 4: transfer the gas filter chamber (206) into the optical path, obtain the time value corresponding to the corresponding gas absorption peak, compare it with the theoretical wave number position corresponding to the absorption peak obtained by HITRAN, and make a one-to-one correspondence between the two to know the frequency domain position corresponding to the gas absorption peak; Step 5: Change the time axis of the long pulse spectrum signal into the frequency domain axis expressed in wave numbers. Time-frequency conversion: convert the data sequence number into time, and then into wave numbers.

7. The method for automatic calibration of quantum cascade laser and inversion of gas concentration according to claim 6, characterized in that: The fitting equation in step 3 is: y=Intercept+B1*x+B2*x 2 +B3*x 3 Among them, Intercept is a function, which refers to the distance from the intersection of the function graph and the coordinate axis to the origin; B1, B2, B3 are cubic function coefficients; x, y are the positions of the peak and trough respectively.

8. The quantum cascade laser automatic calibration and gas concentration inversion device according to claim 7, characterized in that: The value of B1 is 0.48327±0.00504; the value of B2 is -0.00137±3.0727E-5; and the value of B3 is 1.6479E-6±5.92536E-8.

9. The method for automatic calibration of quantum cascade laser and inversion of gas concentration according to claim 6, characterized in that: The following two formulas are used in step 5: t=x÷N v=a×t^3+b×t^2+c×t+d Among them, x is the data sequence number, N is the detector scanning frequency, t is the time, a, b, c, d are the polynomial coefficients, and v is the wave number.

10. The method for automatic calibration of quantum cascade laser and inversion of gas concentration according to claim 6, characterized in that: The specific operation of quantum cascade laser gas concentration inversion in the quantum cascade laser automatic calibration and gas concentration inversion method includes the following steps: S1. First, take the baseline area of ​​the transmission spectrum, use a quadratic polynomial to obtain the baseline, convert the transmission spectrum into an absorbance spectrum, and obtain the absorbance spectrum of the substance; S2. Perform multiple sets of Voigt line parameter fitting modeling on the absorbance spectra of standard substances to obtain a standard substance spectrum library, in which the intensity and line width will change due to the influence of temperature and pressure, in preparation for subsequent concentration inversion; S3. Using the least squares method, by comparing the absorbance data of the standard substance Voigt model, the concentration of the gas substance in the measured data is obtained, thereby realizing gas concentration inversion.

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