Rapid temperature measurement method and device based on micro-air-chamber double-absorption spectrum

Abstract

The invention discloses a rapid temperature measurement method and device based on micro-air-chamber double absorption spectrums, and belongs to the field of laser absorption spectrum sensing. The device comprises a light source module, a linear frequency sweep control module, a temperature measurement module and a signal acquisition and temperature calculation module. According to the invention, the scanning source, the optical fiber Mach-Zehnder interferometer and the feedback control circuit are utilized to ensure the optical frequency sweeping linearity, and two absorption spectral lines with known frequency difference and carrying temperature information are generated through the acousto-optic modulator. The method comprises the following steps: mapping an absorption spectrum from a time domain to a frequency domain on the basis that the time difference of the same absorption peak on two absorption spectrums with fixed frequency difference on a time domain corresponds to the driving frequency of an acoustic optical modulator, namely delta T = T1-T2 corresponds to the driving frequency f of the acoustic optical modulator, and then calculating by extracting parameters related to temperature on the absorption spectrum of the frequency domain to obtain the temperature of the air chamber. The invention can solve the problem of complexity of the traditional Doppler broadening temperature measurement system, and has the advantages of small measurement volume, low cost, high speed, high stability, strong adaptability and the like.

Description

Technical Field

[0001] The invention belongs to the field of laser absorption spectrum sensing and relates to a rapid optical temperature measurement method and device based on micro-gas chamber laser absorption spectrum. Background Art

[0002] The substance being measured forms a laser absorption spectrum by absorbing light of different specific wavelengths. The absorption spectrum carries information about the substance being measured. Taking gas as an example, the gas absorption spectrum contains state information such as temperature, pressure, flow rate, concentration, etc. It is this characteristic that makes laser absorption spectrum widely used in the field of sensing, such as trace detection, component analysis, temperature sensing, etc. The gas absorption spectrum sensing system has significant advantages such as high resolution, high sensitivity, and non-contact measurement. Therefore, laser absorption spectroscopy shows great development prospects in the field of sensing with its unique advantages.

[0003] Temperature measurement technology based on laser absorption spectroscopy is gradually replacing traditional temperature sensors to achieve applications in more fields and extreme environments. At present, there are two temperature measurement methods based on laser absorption spectroscopy, namely, the method based on spectral line intensity and the method based on spectral line width. Among them, the former is easily affected by the external environment, which reduces the measurement accuracy. The latter traces the temperature measurement to the time frequency quantity, has high accuracy, and does not require calibration, can achieve primary temperature measurement, and has a very broad application prospect.

[0004] However, the main difficulty of the temperature measurement method based on spectral line width is the need to accurately control the spectral line scanning interval or calibrate the half-width of the absorption peak. In order to obtain the absorption spectrum, the laser needs to be regulated to achieve optical frequency scanning. Usually, the output wavelength of the semiconductor laser is not strictly linear with the input signal. For this reason, it is necessary to use high-precision standards such as ultra-stable cavities and wavelength meters to control or monitor the spectral line scanning process. Although this method has the characteristics of high precision, it has the disadvantages of complex system, long measurement time, large size, and expensive standard tools, which makes it difficult to achieve miniaturization and practical application. At present, there is no rapid measurement and practical solution for the temperature measurement method based on spectral line width. Summary of the invention

[0005] The purpose of the present invention is to provide a rapid temperature measurement method and device based on a micro-gas chamber dual absorption spectrum, using a scanning source, a fiber Mach-Zehnder interferometer and a feedback control circuit to ensure the linearity of optical frequency sweeping, and generating two absorption spectra with a known frequency difference and temperature information through an acousto-optic modulator. Based on the same absorption peak time difference on the two absorption spectra with a fixed frequency difference in the time domain being equal to the acousto-optic modulator driving frequency, that is, ΔT=T1-T2 corresponding to the acousto-optic modulator driving frequency f, the absorption spectrum is mapped from the time domain to the frequency domain, and then the temperature of the gas chamber is calculated by extracting the parameters related to temperature on the frequency domain absorption spectrum. The present invention can solve the complex problems of the traditional Doppler broadening temperature measurement system, and has the advantages of small measurement volume, low cost, fast speed, high stability, strong adaptability, etc.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] The invention discloses a rapid temperature measurement device based on a micro-gas chamber double absorption spectrum, comprising a light source module, a linear frequency sweep control module, a temperature measurement module, and a signal acquisition and temperature solution module; the light source module is used to provide a narrow line width wide tuning frequency sweep laser; the linear frequency sweep control module realizes optical linear frequency sweep based on a scanning source, an optical fiber Mach-Zehnder interferometer and a control circuit; the temperature measurement module generates two micro-gas chamber absorption spectrum signals carrying temperature information through an acousto-optic modulator; the data acquisition and temperature solution module is used to acquire two absorption spectra, and solve the temperature of the gas chamber according to the two absorption spectra.

[0008] The output light of the light source module is divided into two beams, and the two beams enter the linear frequency sweep control module and the temperature measurement module respectively at the same time. The linear frequency sweep control module uses a scanning source, a fiber Mach-Zehnder interferometer and a feedback control circuit to control the output light of the light source module to realize linear frequency sweep. The scanning source outputs a sawtooth wave, so that the output light of the light source module covers the atomic or molecular absorption line. After the output light of the light source module enters the fiber Mach-Zehnder interferometer, it is divided into two paths, one is a fiber jumper, and the other is a delay fiber. After the two paths are merged, the beat frequency in the detector generates a linear frequency sweep correction signal, and the feedback control circuit is used to achieve the stability of the beat frequency signal to ensure the linear output of the optical frequency during the frequency sweep. The injected current and the output optical frequency during the sawtooth wave frequency sweep are nonlinear. Through the scanning source, the fiber Mach-Zehnder interferometer and the feedback control circuit, the linearity of the optical frequency during the frequency sweep process is significantly improved. The temperature measurement module uses an acousto-optic modulator to generate two absorption spectrum signals with a known frequency difference and related to temperature. The time interval between the appearance of the same absorption peak in the two absorption spectra corresponds to the acousto-optic modulator driving frequency f. Combined with the linear frequency sweep control module and the temperature measurement module, on the basis of ensuring that the output light of the light source module realizes linear frequency sweep, based on the principle that the time difference of the same peak of two spectral lines on two absorption spectral lines corresponds to the driving frequency, that is, ΔT=T1-T2 corresponds to the driving frequency f of the acousto-optic modulator, the frequency calibration of the absorption spectrum signal is realized, and then the absorption spectrum is mapped from the time domain to the frequency domain. The mapping from the time domain to the frequency domain is equivalent to the traditional Doppler broadening temperature measurement process, and the optical frequency sweep is generated by the standard tool or the super-temperature cavity method, and then the Doppler broadening height of the frequency domain absorption spectrum is extracted, and finally substituted into the temperature measurement formula to obtain the thermodynamic temperature.

[0009] Furthermore, the light source module includes a narrow linewidth laser, an optical isolator, a half-wave plate, and a polarization beam splitter prism; the narrow linewidth laser outputs a narrow linewidth frequency modulated continuous wave to cover the atomic or molecular absorption spectrum. The optical isolator prevents the reflected light from the optical path from affecting the light source; the half-wave plate and the polarization beam splitter prism are used in combination to adjust the ratio of reflected light to transmitted light. After the output light of the narrow linewidth laser passes through the optical isolator and the half-wave plate, it enters the polarization beam splitter prism and is divided into two paths, one path enters the linear frequency sweep control module, and the other path enters the temperature measurement module to generate an absorption spectrum.

[0010] Furthermore, the linear frequency sweep control module includes a sweep source, a fiber coupler, a fiber Mach-Zehnder interferometer, a photodetector, a multiplier, a reference frequency source, a frequency detector, a low-pass filter, and an adder. The sweep source outputs a sawtooth wave and is loaded into a narrow linewidth laser to realize the optical frequency sweep function; the fiber coupler is used to collect the reflected light of the polarization beam splitter prism; the fiber Mach-Zehnder interferometer and the photodetector are combined to provide a nonlinear correction signal in real time during the optical frequency sweep process. The multiplier realizes the mixing function of the nonlinear correction signal and the reference frequency source; the frequency detector is used to receive the mixing signal and generate a feedback control electrical signal; the low-pass filter is used to filter out the influence of high-frequency signals in the feedback control electrical signal. The adder superimposes the sawtooth wave signal and the electrical signal output by the low-pass filter. The reflected light of the polarization beam splitter prism enters the Mach-Zehnder interferometer through the fiber coupler, and the two-arm light signals beat in the photodetector to form a nonlinear correction signal. The nonlinear correction signal enters the multiplier and is mixed with the reference frequency source output signal. The mixed electrical signal enters the frequency detector to generate a feedback control signal, and after passing through a low-pass filter and an adder, it is superimposed with the sawtooth wave signal and input into the narrow linewidth laser control port. The linear frequency sweep control module uses a scanning source, an optical fiber Mach-Zehnder interferometer and a feedback control circuit to realize the linear frequency sweep of the output light of the light source module. The scanning source outputs a sawtooth wave, so that the output light of the light source module covers the atomic or molecular absorption line. After the output light of the light source module enters the optical fiber Mach-Zehnder interferometer, it is divided into two paths, one is a fiber jumper, and the other is a delay fiber. After the two paths are merged, the beat frequency in the detector generates a nonlinear correction signal, and the nonlinear correction signal is stabilized by the feedback control circuit, thereby ensuring the linear output of the optical frequency during the frequency sweep process.

[0011] Furthermore, the temperature measurement module includes a half-wave plate, an acousto-optic modulator, an air-temperature and room temperature control module, a MEMS air chamber, a first lens, a first detector, a second lens, and a second detector. The half-wave plate is used to adjust the polarization direction of the light transmitted by the polarization beam splitter prism; the acousto-optic modulator generates two beams of diffracted light of order 0 and order +1; the air-temperature and room temperature control module provides high-precision temperature control and magnetic shielding functions for the MEMS micro air chamber; the MEMS micro air chamber is a temperature sensor; the first lens is combined with the first detector to realize the collection of the 0th order diffracted light; the second lens is combined with the second detector to realize the collection of the +1st order diffracted light. The light transmitted by the polarization beam splitter prism passes through the half-wave plate and the acousto-optic modulator to generate the 0th order and +1st order diffracted light, and these two beams of light interact with the MEMS air chamber inside the air-temperature and room temperature control module, and then the two beams of light carrying temperature information are collected by the corresponding detectors through the corresponding lenses respectively. The temperature measurement module uses an acousto-optic modulator to generate two absorption spectrum signals with a known frequency difference and related to temperature. The time difference between the same peak of the two spectrum lines on the two absorption spectrum lines corresponds to the acousto-optic modulator driving frequency, that is, ΔT=T1-T2 corresponds to the acousto-optic modulator driving frequency f, thereby realizing the absorption spectrum frequency calibration.

[0012] Furthermore, the signal acquisition and temperature calculation module includes a signal acquisition module and a temperature calculation module. The signal acquisition module collects the sawtooth wave and the absorption spectrum signals output by the two detectors at a preset sampling rate; the temperature calculation module calculates the temperature of the air chamber according to the two absorption spectrum lines obtained by the acquisition to obtain the temperature of the air chamber.

[0013] A rapid temperature measurement method based on micro-gas chamber double absorption spectrum is implemented based on the rapid temperature measurement device based on micro-gas chamber double absorption spectrum, wherein the temperature solution module solves the temperature of the gas chamber according to the two absorption spectrum lines collected, and the implementation method includes the following steps:

[0014] Step 1: Test data plotting. The three electrical signals input to the signal acquisition module are plotted into the same coordinate system at a preset sampling rate. The three signals are sawtooth wave signals, 0-order diffraction light absorption spectrum, and +1-order diffraction light absorption spectrum. The horizontal axis is time, and the vertical axis is voltage value.

[0015] Step 2: Single-cycle processing: Divide the multi-cycle data into multiple groups of single-cycle data according to the starting point of the sawtooth wave, and each group contains the complete 0th and +1st order diffraction light absorption spectrum curves.

[0016] Step 3: Mapping from time domain to frequency domain. In the same coordinate system, select a set of single-cycle data and obtain the time difference of the same absorption peak from the 0th and +1st order diffraction light absorption spectrum curves. This time difference corresponds to the AOM driving frequency, that is, ΔT = T1-T2 corresponds to the AOM driving frequency f. Through the correspondence between the time difference and the driving frequency, the absorption spectrum is converted from the time domain to the frequency domain. T1 and T2 are the times when the same peak appears on the 0th and +1st order diffraction lines, respectively.

[0017] Step 4: Temperature calculation. Calculate the temperature by converting the 0th-order absorption spectrum into the frequency domain, fit the curve and obtain the absorption peak Doppler half-width, and then calculate the temperature according to the following temperature formula

[0018]

[0019] Where: M is the atomic or molecular mass; v0 is the center frequency of the spectral line, Δv D is the Doppler half-width of the absorption peak; T is the thermodynamic temperature.

[0020] Beneficial effects:

[0021] 1. The traditional Doppler broadening temperature measurement field requires the use of standard instruments such as wavelength meters and ultra-stable cavities. These standard instruments are large in size and high in cost, making it difficult to achieve miniaturization, practicality, and integration. The present invention discloses a fast optical temperature measurement method and device based on micro-gas chamber double absorption spectrum, which uses an optical fiber Mach-Zehnder interferometer, an acousto-optic modulator, and a MEMS micro-gas chamber to achieve temperature measurement, significantly reducing the system volume and having low device cost.

[0022] 2. In the field of traditional Doppler broadening temperature measurement, wavelength meters, ultra-stable cavities and other standard tools are used to achieve frequency stabilization and frequency sweeping functions, resulting in slow temperature measurement speed. The present invention discloses a fast optical temperature measurement method and device based on a micro-gas chamber double absorption spectrum, which uses a scanning source, a fiber Mach-Zehnder interferometer and a feedback control circuit to achieve optical linear frequency sweeping, and the fast frequency sweeping process corresponds to the temperature measurement process. This method does not require the traditional frequency sweeping method to measure at equally spaced points in sequence, and omits the single-point frequency stabilization process in the traditional frequency sweeping process, which significantly improves the temperature measurement speed, and the measurement time is increased from the traditional more than ten minutes to seconds.

[0023] 3. The laser output wavelength and the injected current are nonlinear, which leads to the introduction of errors when only sawtooth wave is used to control the laser frequency sweep for temperature measurement. The present invention discloses a fast optical temperature measurement method and device based on a micro-gas chamber double absorption spectrum. On the basis of realizing optical linear frequency sweep using a scanning source, an optical fiber Mach-Zehnder interferometer and a feedback control circuit, an acousto-optic modulator is used to generate two absorption spectrum lines and the spectrum frequency is calibrated according to the corresponding driving frequency according to the time difference of the same absorption peak. The present invention can solve the influence of nonlinear errors when a single sawtooth wave is used to control the laser, and has high measurement accuracy.

[0024] 4. The traditional Doppler broadening temperature measurement device system is complex and easily affected by the external environment, such as vibration. The invention discloses a rapid optical temperature measurement method and device based on micro-gas chamber double absorption spectrum. On the basis of achieving the above beneficial effects 1, 2, and 3, it is easier to integrate through integrated optical circuits and integrated circuits. The integrated test system has the advantages of high integration, simple structure, and good environmental adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of a rapid temperature measurement device based on micro-gas chamber double absorption spectrum of the present invention.

[0026] Among them: 1—light source module, 2—linear frequency sweep control module, 3—temperature measurement module, 4—signal acquisition and temperature calculation module;

[0027] 101—narrow linewidth laser, 102—optical isolator, 103—half-wave plate, 104—polarization beam splitter prism;

[0028] 201—scanning source, 202—fiber coupler, 203—fiber Mach-Zehnder interferometer, 204—photodetector, 205—multiplier, 206—reference frequency source, 207—frequency detector, 208—low-pass filter, 209—adder;

[0029] 301—half-wave plate, 302—acousto-optic modulator, 303—air and room temperature control module, 304—MEMS air chamber, 305—first lens, 306—first detector, 307—second lens, 308—second detector;

[0030] 401 - acquisition module, 402 - temperature calculation module. DETAILED DESCRIPTION

[0031] In order to better illustrate the purpose and advantages of the present invention, the invention is further described below with reference to the accompanying drawings and examples.

[0032] Embodiment 1:

[0033] like Figure 1 As shown, the embodiment discloses a rapid temperature measurement device based on dual absorption spectra of micro gas chamber, including a light source module 1, a linear frequency sweep control module 2, a temperature measurement module 3, and a signal acquisition and temperature solution module 4. The light source module 1 provides a frequency sweep laser that can cover the D1 line of cesium atoms; the linear frequency sweep control module 2 is used to realize the laser linear frequency sweep function; the temperature measurement module is used to obtain two absorption spectra with known frequency difference (i.e., the frequency difference is 350MHz at the same time) and carrying temperature information; the signal acquisition and temperature solution module 4 is used for signal acquisition and processing, and solves the temperature of the gas chamber.

[0034] The MEMS micro-gas chamber is realized by semiconductor processing technology and is filled with cesium (Cs) single substance. The laser is a distributed Bragg reflector (DBR) laser, but it is not limited to this type. The laser output frequency can cover the D1 line of cesium atoms. The driving frequency of the acousto-optic modulator is 350MHz. The fiber length of the delay arm of the Mach-Zehnder interferometer is 5km.

[0035] The light source module 1 includes a narrow line width laser 101, an optical isolator 102, a half-wave plate 103, and a polarization beam splitter prism 104. The output light of the narrow line width laser 101 passes through the optical isolator 102, the half-wave plate 103, and the polarization beam splitter prism 104 in sequence and is divided into two paths. The optical isolator 102 is used to prevent the reflected light from affecting the laser. The half-wave plate 103 and the polarization beam splitter prism 104 are used to adjust the splitting ratio of the two paths of light, one path enters the linear sweep control module 2, and the other path enters the temperature measurement module 3 to generate an absorption spectrum.

[0036] The linear frequency sweep control module 2 includes a sweep source 201, a fiber coupler 202, a fiber Mach-Zehnder interferometer 203, a photodetector 204, a multiplier 205, a reference frequency source 206, a frequency detector 207, a low-pass filter 208, and an adder 209. The sweep source 201 outputs a sawtooth wave electrical signal to realize the frequency sweep output of the narrow linewidth laser 101, with a frequency of 5 Hz and an amplitude of 400 mV. The reflected light of the polarization beam splitter 104 passes through the fiber coupler 202 and enters the fiber Mach-Zehnder interferometer 203. After the two-arm light signals are merged, they enter the photodetector 204 and beat to obtain a nonlinear correction signal. The nonlinear correction signal enters the multiplier 205 and is mixed with the reference frequency source 206. The mixed electrical signal enters the frequency detector 207 to obtain the feedback control electrical signal. The feedback control electrical signal is then superimposed with the sawtooth wave signal through the low-pass filter 208 and the adder 209 and enters the control signal input end of the narrow linewidth laser 101. The fiber coupler 202 is used to couple the reflected light of the polarization beam splitter 104 into the optical fiber. The fiber Mach-Zehnder interferometer 203 and the photodetector 204 are combined to obtain the nonlinear correction beat signal. The multiplier 205 is used to realize the mixing of the output signal of the reference frequency source 206 and the beat signal. The frequency detector 207 is used to receive the mixing signal and output the feedback control signal. The low-pass filter 208 is used to filter out the high-frequency signal in the feedback control signal; the adder 209 is used to realize the superposition of the feedback control signal and the sawtooth wave signal. The linear frequency sweep control module 2 uses a series of circuit devices including a scanning source 201 and an optical fiber Mach-Zehnder interferometer 203 to realize linear frequency sweep of the output light of the light source module 1. The scanning source 201 outputs a sawtooth wave, so that the output light of the light source module 1 covers the D1 line of the cesium atom. After the output light of the light source module 1 enters the optical fiber Mach-Zehnder interferometer 203, it is divided into two paths, one is an optical fiber jumper, and the other is a delay optical fiber. After the two paths are merged, the beat frequency in the detector generates a nonlinear correction signal, and then the beat frequency signal is stabilized through a feedback control circuit composed of a series of electrical devices, thereby ensuring the linear output of the optical frequency during the frequency sweep process.

[0037] The temperature measurement module 3 includes a half-wave plate 301, an acousto-optic modulator 302, an air-temperature temperature control module 303, a MEMS air chamber 304, a first lens 305, a first detector 306, a second lens 307, and a second detector 308. The transmitted light of the polarization beam splitter 104 passes through the half-wave plate 301 and the acousto-optic modulator 302 to generate 0-order and +1-order diffracted light, and the driving frequency of the acousto-optic modulator is 350MHz. After these two beams of diffracted light enter the MEMS air chamber 304 inside the air-temperature temperature control module 303, they interact with cesium atoms to generate two absorption spectra carrying temperature information. Subsequently, the 0-order diffracted light is collected by the first detector 306 through the first lens 305, and the +1-order diffracted light is collected by the second detector 308 through the second lens 307. The half-wave plate 301 is used to adjust the polarization direction of the laser; the acousto-optic modulator is used to generate two diffracted lights with a determined frequency difference; the air-temperature temperature control module 303 is used to maintain the constant temperature of the MEMS air chamber 304 and shield the magnetic field. The temperature measurement module 3 uses the acousto-optic modulator 302 to generate two absorption spectrum signals with a known frequency difference and related to temperature. The time difference of the same peak of the two spectrum lines on the two absorption spectrum lines corresponds to the acousto-optic modulator driving frequency, that is, ΔT=T1-T2 corresponds to the acousto-optic modulator driving frequency f, thereby realizing the absorption spectrum frequency calibration.

[0038] The signal acquisition and temperature calculation module 4 includes a signal acquisition module 401 and a temperature calculation module 402. The sawtooth wave signal and the two absorption spectrum signals collected by the first detector 306 and the second detector 308 are collected by the acquisition module 401 at a fixed sampling rate of 10 kHz, and the collected signals are transmitted to the temperature calculation module 402 for processing and calculation, and finally the temperature of the gas chamber is calculated.

[0039] This embodiment discloses a rapid temperature measurement method based on micro-gas chamber double absorption spectrum. Figure 1 The temperature measuring device is implemented. The temperature calculation module 402 calculates the temperature of the gas chamber according to the two absorption spectra collected, and the specific implementation steps are as follows:

[0040] Step 1: Test data plotting. First, in the temperature calculation module, the three signals collected by the signal acquisition module at the preset sampling rate, namely the sawtooth wave electrical signal output by the scanning source, the 0th order diffraction light absorption spectrum signal, and the +1st order diffraction light absorption spectrum signal, are plotted in the same coordinate system, with the horizontal axis being time and the vertical axis being voltage amplitude. The sampling rate of the signal acquisition module is 10kHz, and the interval between two adjacent points is 0.1ms.

[0041] Step 2: Single-cycle processing. Based on the starting point of the sawtooth wave, the multi-cycle data drawn in step 1 is divided into single-cycle data. The single-cycle data contains a complete cycle of 0th and +1st order diffraction light absorption spectrum signals for subsequent processing.

[0042] Step 3: Mapping from time domain to frequency domain. The time difference between the appearance of the same absorption peak of the cesium atomic D1 line in the 0th and +1st order diffraction light absorption spectra corresponds to the driving frequency applied to the acousto-optic modulator 302, i.e., 350 MHz, and the optical frequency change corresponding to 0.1 ms is calculated. The horizontal axis is then converted from time to frequency to obtain the absorption spectrum in the frequency domain.

[0043] Step 4: Temperature calculation. Calculate the temperature using the 0th-order absorption spectrum converted to the frequency domain. Fit the 0th-order spectrum to obtain the Doppler half-width of the D1 line absorption peak, and then calculate the thermodynamic temperature according to the following formula:

[0044]

[0045] Where: M is the atomic or molecular mass; v0 is the center frequency of the spectral line, Δv D is the Doppler half-width of the absorption line; T is the thermodynamic temperature.

[0046] Each of the above steps is implemented in a matlab program, and each step corresponds to a matlab programming algorithm.

[0047] The specific description above further illustrates the purpose, technical solutions and beneficial effects of the invention in detail. It should be understood that the above is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A rapid temperature measurement device based on micro-gas chamber double absorption spectrum, characterized in that: The invention comprises a light source module (1), a linear frequency sweep control module (2), a temperature measurement module (3), and a signal acquisition and temperature calculation module (4); the light source module (1) is used to provide narrow line width wide tuning frequency sweep laser; the linear frequency sweep control module (2) realizes optical linear frequency sweep based on a sweep source, an optical fiber Mach-Zehnder interferometer, and a feedback control circuit; the temperature measurement module (3) generates two micro-gas chamber absorption spectrum signals carrying temperature information through an acousto-optic modulator; the data acquisition and temperature calculation module (4) is used to acquire two absorption spectra and calculate the temperature of the gas chamber according to the two absorption spectra; The light output from the light source module (1) is divided into two beams of light, and the two beams of light enter the linear frequency sweep control module (2) and the temperature measurement module (3) respectively at the same time; the linear frequency sweep control module (2) uses a sweep source, an optical fiber Mach-Zehnder interferometer and a feedback control circuit to control the light output from the light source module (1) to achieve linear frequency sweep; the sweep source outputs a sawtooth wave, so that the light output from the light source module (1) covers the atomic or molecular absorption line; the light output from the light source module (1) is divided into two paths after entering the optical fiber Mach-Zehnder interferometer, one path is an optical fiber jumper, and the other path is a time-delay optical fiber; after the two paths are combined, they beat in the detector to generate a frequency sweep nonlinear correction signal, and the feedback control circuit is used to achieve the stability of the nonlinear correction signal, thereby ensuring the linear output of the optical frequency during the frequency sweep; the injected current during the sawtooth wave frequency sweep has a nonlinear relationship with the output optical frequency. , through a scanning source, an optical fiber Mach-Zehnder interferometer and a feedback control circuit, the optical frequency linearity of the frequency sweeping process is significantly improved; the temperature measurement module (3) uses an acousto-optic modulator to generate two absorption spectrum signals with a known frequency difference and related to temperature, and the time difference of the same absorption peak in the two absorption spectra corresponds to the driving frequency f of the acousto-optic modulator; combined with the linear frequency sweeping control module (2) and the temperature measurement module (3), on the basis of ensuring that the output light of the light source module (1) realizes linear frequency sweeping, based on the principle that the time difference of the same peak of the two spectrum lines on the two absorption spectrum lines corresponds to the driving frequency, that is, ΔT=T1-T2 corresponds to the driving frequency f of the acousto-optic modulator, the frequency calibration of the absorption spectrum signal is realized, and then the absorption spectrum is mapped from the time domain to the frequency domain; the Doppler half-width of the frequency domain absorption spectrum is extracted, and then substituted into the temperature measurement formula to obtain the thermodynamic temperature.

2. The rapid temperature measurement device based on micro-gas chamber double absorption spectrum according to claim 1, characterized in that: The light source module (1) comprises a narrow linewidth laser (101), an optical isolator (102), a half-wave plate (103), and a polarization beam splitter prism (104); the narrow linewidth laser (101) outputs a narrow linewidth frequency modulated continuous wave to cover the atomic or molecular absorption spectrum; the optical isolator (102) prevents the reflected light of the optical path from affecting the light source; the half-wave plate (103) and the polarization beam splitter prism (104) are used in combination to adjust the ratio of reflected light to transmitted light; after the output light of the narrow linewidth laser (101) passes through the optical isolator (102) and the half-wave plate (103), it enters the polarization beam splitter prism (104) and is divided into two paths, one path enters the linear frequency sweep control module (2), and the other path enters the temperature measurement module (3) to generate an absorption spectrum.

3. The rapid temperature measurement device based on micro-gas chamber double absorption spectrum according to claim 1, characterized in that: The linear frequency sweep control module (2) comprises a sweep source (201), a fiber coupler (202), a fiber Mach-Zehnder interferometer (203), a photodetector (204), a multiplier (205), a reference frequency source (206), a frequency detector (207), a low-pass filter (208), and an adder (209); the sweep source (201) outputs a sawtooth wave which is loaded onto a narrow linewidth laser (101) to realize an optical frequency sweep function; the fiber coupler (202) is used to collect light reflected by a polarization beam splitter (104); The Hertz-Zehnder interferometer (203) and the photodetector (204) are combined to provide a nonlinear correction signal in real time during an optical frequency sweep process; the multiplier (205) realizes a frequency mixing function of the nonlinear correction signal and a reference frequency source (206); the frequency detector (207) is used to receive the mixing signal and generate a feedback control electrical signal; the low-pass filter (208) is used to filter out the influence of high-frequency signals in the feedback control electrical signal; the adder (209) superimposes the sawtooth wave signal and the electrical signal output by the low-pass filter (208); and the polarization splitter (209) is used to generate a feedback control electrical signal. The reflected light from the prism (104) enters the Mach-Zehnder interferometer (203) through the optical fiber coupler (202), and the two-arm optical signals beat in the photodetector (204) to form a nonlinear correction signal; the nonlinear correction signal enters the multiplier (205) and is mixed with the output signal of the reference frequency source (206), and the mixed electrical signal enters the frequency detector (207) to generate a feedback control signal, and is superimposed with the sawtooth wave signal after passing through a low-pass filter (208) and an adder (209) and input to the control port of the narrow linewidth laser (101); the linear The frequency sweep control module (2) uses a sweep source, an optical fiber Mach-Zehnder interferometer and a feedback control circuit to realize linear frequency sweep of the output light of the light source module (1); the sweep source outputs a sawtooth wave so that the output light of the light source module (1) covers the atomic or molecular absorption line; the output light of the light source module (1) is divided into two paths after entering the optical fiber Mach-Zehnder interferometer, one path is an optical fiber jumper and the other path is a delay optical fiber, and after the two paths are merged, a beat frequency nonlinear correction signal is generated in the detector, and the beat frequency nonlinear correction signal is stabilized by the feedback control circuit, thereby ensuring the linear output of the optical frequency during the frequency sweep process.

4. The rapid temperature measurement device based on micro-gas chamber double absorption spectrum according to claim 1, characterized in that: The temperature measurement module (3) comprises a half-wave plate (301), an acousto-optic modulator (302), an air-temperature and air-control module (303), a MEMS air chamber (304), a first lens (305), a first detector (306), a second lens (307), and a second detector (308); the half-wave plate (301) is used to adjust the polarization direction of light transmitted by the polarization beam splitter prism (104); the acousto-optic modulator (302) generates two beams of diffracted light, 0th order and +1st order; the air-temperature and air-control module (303) provides high-precision temperature control and magnetic shielding functions for the MEMS micro air chamber (304); the MEMS micro air chamber (304) is a temperature sensor; the first lens (305) and the first detector (306) are combined to realize the 0th order diffraction light collection; the second lens (307) and the second detector (308) are combined to realize +1 order diffraction light collection; the polarization beam splitter (104) transmits light through a half-wave plate (301) and an acousto-optic modulator (302) to generate 0th order and +1st order diffraction light, and the two beams of light interact with the MEMS air chamber (304) inside the air and temperature control module (303), and then the two beams of light carrying temperature information are collected by corresponding detectors through corresponding lenses respectively; the temperature measurement module (3) uses the acousto-optic modulator to generate two absorption spectrum signals with known frequency difference and related to temperature, and the time difference of the same peak on the two absorption spectrum lines corresponds to the acousto-optic modulator driving frequency, that is, ΔT=T1-T2 corresponds to the acousto-optic modulator driving frequency f, thereby realizing absorption spectrum frequency calibration.

5. The rapid temperature measurement device based on micro-gas chamber double absorption spectrum according to claim 1, characterized in that: The signal acquisition and temperature calculation module (4) comprises a signal acquisition module (401) and a temperature calculation module (402); the signal acquisition module (401) acquires the sawtooth wave and the absorption spectrum signals output by the two detectors at a preset sampling rate; the temperature calculation module (402) performs calculation processing on the temperature of the gas chamber according to the two absorption spectrum lines acquired, so as to obtain the temperature of the gas chamber.

6. A rapid temperature measurement method based on micro-gas chamber double absorption spectrum, implemented based on a rapid temperature measurement device based on micro-gas chamber double absorption spectrum as claimed in claim 1, 2, 3, 4 or 5, characterized in that: The temperature calculation module (402) calculates the temperature of the gas chamber according to the two collected absorption spectra, and the implementation method includes the following steps: Step 1: plotting test data; plotting three electrical signals input to the signal acquisition module (401) to the same coordinate system at a preset sampling rate, wherein the three signals are sawtooth wave signals, a 0-order diffraction light absorption spectrum, and a +1-order diffraction light absorption spectrum, the horizontal axis is time, and the vertical axis is voltage value; Step 2: Single cycle processing; The multi-cycle data is divided into multiple groups of single-cycle data according to the starting point of the sawtooth wave, and each group contains the complete 0th and +1st order diffraction light absorption spectrum curves; Step 3: Mapping from time domain to frequency domain; in the same coordinate system, a set of single-cycle data is selected to obtain the time difference of the same absorption peak from the 0th order and +1st order diffraction light absorption spectrum curves, the time difference corresponds to the driving frequency of the acousto-optic modulator (302), that is, ΔT=T1-T2 corresponds to the driving frequency f of the acousto-optic modulator, and the absorption spectrum is converted from the time domain to the frequency domain through the corresponding relationship between the time difference and the driving frequency; T1 and T2 are the time when the same peak appears on the 0th order and +1st order diffraction spectrum lines respectively; Step 4: Temperature calculation: Calculate the temperature by converting the 0th-order absorption line into the frequency domain, fit the curve and obtain the absorption peak Doppler half-width, and then calculate the temperature according to the following temperature formula: Where: M is the atomic or molecular mass; v0 is the center frequency of the spectral line, Δv D is the Doppler half-width of the absorption peak; T is the thermodynamic temperature.

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