78 results about "Photoacoustic effect" patented technology

The invention discloses a porcelain insulator nondestructive testing device and method based on chirp modulation photoacoustic spectroscopy. The device comprises a signal generator, a signal processing module and a signal processing module, the laser is connected with the signal generator; the power amplifier is connected with the laser; the laser collimator is connected with the power amplifier; and the signal collector collects the sound wave signals, converts the sound wave signals into electric signals, transmits the electric signals to the computer through a cable for data processing, obtains a spectrogram of the sound wave signals, and judges whether defects exist in the porcelain insulator or not according to the spectrogram. According to the porcelain insulator nondestructive testing device adopting chirp modulation and photoacoustic spectroscopy, characteristic frequency scanning is achieved through chirp modulation, a porcelain insulator acoustic signal spectrogram is obtained through the solid photoacoustic effect, non-power-cut nondestructive testing of porcelain insulators can be achieved, and the detection efficiency of porcelain insulator defects is greatly improved.

The present invention discloses a multi-component gas concentration detection system, which relates to the field of gas concentration detection, and comprises: a light source, which is used for emitting detection light covering the absorption wave band of a target gas; the light splitting assembly is used for dispersing the detection light and at least splitting the detection light into a first light beam and a second light beam; the air chamber is provided with an optical signal detection module and an acoustic signal detection module; the first light modulator is used for carrying out wavelength selection and modulation on the second light beam; wherein the first light beam is received by the light signal detection module to form an absorption spectrum detection light path; the second light beam is absorbed by the gas to be detected and then excites a sound wave signal through a photoacoustic effect, and the sound wave signal is received by the sound signal detection module to form a photoacoustic spectrum detection light path. By adopting the scheme, synchronous detection of multi-component gas, compactness of a detection structure and high-sensitivity detection of low-concentration gas can be considered.

The invention relates to the field of ultrasonic flaw detection, in particular to an ultrasonic nondestructive flaw detection system based on a photoacoustic effect, which comprises a photoacoustic excitation module used for emitting excitation laser to scan the surface of a detected object and inducing the photoacoustic effect to generate ultrasonic waves on the surface of the detected object through the excitation laser; the optical detection module comprises a detection laser and a four-quadrant detector, the detection laser is used for emitting detection laser, the detection laser is incident to a detection point on the surface of the detected object at a preset inclination angle, and the four-quadrant detector is used for receiving the detection laser reflected by the detection point; and the computer is connected with the four-quadrant detector, and is used for receiving the current signal output by the four-quadrant detector, calculating the light spot offset of the center of the detection light spot relative to the center of the four-quadrant detector, and calculating the internal damage position of the detected object by analyzing the time domain characteristic of the light spot offset. According to the invention, the defects of contact detection limitation and coherent light interference technology are overcome, the sensitivity and applicability are improved, and the cost is reduced.

The invention discloses non-contact photoacoustic imaging equipment and method based on leakage Lamb wave detection, in the equipment, a photoacoustic excitation unit excites Lamb waves on the surface of a to-be-detected plate-shaped sample through a photoacoustic effect; the automatic scanning unit drives the to-be-detected plate-shaped sample to move along the scanning direction, so that the two-dimensional full-coverage scanning of the to-be-detected plate-shaped sample by the photoacoustic excitation unit is realized; the signal detection and amplification unit captures the leakage Lamb wave signal and carries out signal amplification; the data acquisition unit acquires the amplified signal in real time and transmits the signal data to the signal processing and imaging end; and the signal processing and imaging end is respectively in communication connection with the photoacoustic excitation unit, the automatic scanning unit and the data acquisition unit, and performs signal acquisition, storage, analysis and imaging processing. The photoacoustic effect excitation technology, the high-sensitivity signal detection technology and the automatic scanning imaging technology are fused, and efficient, accurate and non-contact detection of the surface and subsurface defects of the plate-shaped material is achieved.

Apparatus and methods are described for treating an occlusion in a blood vessel. A catheter is inserted into the blood vessel. An irradiation unit is driven to emit probing radiation such that the probing radiation is directed toward the occlusion, and returning radiation which is returned in response to the probing radiation impacting the occlusion, is detected. A composition of at least a portion of the occlusion is derived based on a signature that is indicative of the composition within the returning radiation. The irradiation unit is driven to irradiate the portion of the occlusion by emitting treatment radiation having a set of irradiation parameters. The set of irradiation parameters is determined to modulate between a photoacoustic effect of the treatment radiation and a photothermal effect of the treatment radiation, based on the composition of the portion of the occlusion. Other applications are also described.

The invention relates to a near-infrared two-region small organic molecule fluorescent probe with a photoacoustic effect and a preparation method and application thereof.The NIR-II small fluorescent molecule is of a tripolymer structure, is obtained by polymerizing three benzothiadiazole near-infrared two-region small organic molecules through the Schiff base generation reaction of amino and ketone, has good biocompatibility, and can be used for preparing a near-infrared two-region small organic molecule fluorescent probe with the photoacoustic effect. The fluorescence-photoacoustic dual-mode imaging material has the advantages of good optical property, photoacoustic property and photothermal property, no toxicity, good biocompatibility, easy absorption and metabolism by organisms, and realization of fluorescence-photoacoustic dual-mode imaging of osteosarcoma mice.

The application discloses a kind of resonance quartz enhanced dual optical comb photoacoustic spectroscopy gas detection devices, device includes dual optical comb source, acoustooptic frequency shift component, quartz resonant component, signal amplification component, phase-sensitive demodulation component and normalization component;Dual optical comb source is as the excitation light source of photoacoustic effect, it realizes real-time frequency shift by acoustooptic frequency shift component;Dual optical comb source is emitted by acoustooptic frequency shift component and after acting on gas molecule, produces multi-heterodyne sound wave, and quartz resonant component extracts resonance component therein and converts it into electrical signal;The electrical signal generated is successively processed by signal amplification component, phase-sensitive demodulation component, normalization component, and the composition discrimination of target gas and concentration inversion are realized by signal after processing.This application improves the structure and detection mode of dual optical comb photoacoustic spectroscopy, completes the resonance detection of dual optical comb photoacoustic spectroscopy, improves the detection sensitivity of system by acoustic and electrical two-stage filtering, and increases the dynamic range of system.

The invention relates to a photoacoustic liquid viscosity detection device and method based on spectrum resolution, and belongs to the field of photoacoustic detection and liquid physical property analysis. The device comprises a solid-state laser, a collimating lens, a plane mirror, a plate-type semitransparent mirror, a microscope objective lens, a photodiode, a photoacoustic coupling cavity, a rectangular prism group, an ultrasonic transducer, a pre-signal amplifier, a digital oscilloscope and a computer. Pulse laser is focused to a liquid sample after being processed by an optical path to excite a photoacoustic effect, an ultrasonic transducer receives a signal and converts the signal into an electric signal, after a digital oscilloscope synchronously samples, a computer extracts a frequency spectrum full width at half maximum (FWHM) through fast Fourier transform, and non-contact detection is realized based on a negative correlation between the frequency spectrum full width at half maximum and viscosity. The method can overcome the defects of large sample size, mechanical contact and the like of a traditional method, and is suitable for high-precision viscosity detection of biological tissues and industrial samples in the field of biomedicine.

The application discloses a kind of quick detection device of gas content in transformer oil, it is related to the technical field of power transformer;Quick detection device of gas content in transformer oil includes first air pump, second air pump, gas separation structure, booster oil pump, circulation structure and gas detection device;First air pump forms negative pressure environment above the oil surface in heating inner bag, and carries out atomization spray to oil by circulation structure, can be fully released from dissolved gas in oil, greatly speeds up the gas release speed in oil liquid;After enrichment by pressurization, the gas concentration of the gas after release is improved, to avoid the detection deviation caused by too low gas concentration even missed detection;The application also designs laser detection structure based on photoacoustic effect and heat cleaning structure for removing residual water vapor;The device provided by the application shortens the overall time consumption of gas release and detection in transformer oil, and guarantees the accuracy of oil release gas detection.

The present invention discloses a method for generating sound waves in the air using a pulsed laser. The device for generating sound waves is composed of a pulsed laser and an optical modulation system. The pulsed laser is emitted by a pulsed laser and then acts on water vapor in the air after passing through the optical modulation system. The water vapor absorbs the heat energy of the pulsed laser. After the pulsed laser passes through, the water vapor temperature instantly rises and expands, thereby generating pressure waves in the area of ​​action, that is, generating sound waves through the photoacoustic effect. In addition, a three-color visible light laser is used to illuminate the area of ​​action for imaging. The structure of the method for generating sound waves in the air using laser pulses proposed by the present invention is simple. Since water vapor can still be generated even in air with low relative humidity, the effect can be achieved by only following the above steps. The method has research value in the manipulation of microparticles, biological imaging, space imaging, sound communication, and naked-eye three-dimensional display.

An oxidation corrosion product thickness on-line measurement method based on a photoacoustic effect comprises the following steps: modulating laser with a specific frequency to irradiate on the CRUD surface of a fuel cladding, monitoring an acoustic wave signal emitted by the CRUD surface by using a piezoelectric sensor, and establishing an on-line conversion model of the acoustic wave signal and the CRUD thickness so as to obtain visual thickness real-time data. On the condition that the original environment of the CRUD is not damaged, online in-situ measurement is carried out on the thickness of the CRUD, and it is ensured that the real thickness of the CRUD in the growth environment can be accurately reflected by measurement data. Through the method, the dynamic growth behavior characteristics of the CRUD thickness can be obtained, so that more accurate monitoring and guidance are provided for safe operation and fuel management of a reactor.

The invention provides a differential photoacoustic gas sensing system and method based on cross-correlation demodulation, and is suitable for the fields of trace gas monitoring, industrial process fine control and environment detection. The system comprises a gas excitation light source, a symmetrical double-probe gas sensor, an optical fiber circulator, a wide-spectrum light source, a 1 * 2 optical fiber coupler, two pieces of plain glass, a photoelectric detection array and a computer, acoustic wave signals excited by the photoacoustic effect generate difference superposition cavity length changes on the symmetrically-arranged double cantilever beams, and environment noise triggers cavity length responses which are counteracted in the same direction. The system adopts an optical cross-correlation demodulation algorithm to track peak displacement of a cross-correlation function in real time, dynamically demodulates cavity length change information, and inverts the gas concentration according to the information. According to the design scheme, effective photoacoustic signals are remarkably enhanced, meanwhile, effective suppression of environment vibration noise is achieved, and finally the trace gas detection system integrating the advantages of miniaturization, high sensitivity and low cost is constructed.

The application discloses an online measurement method for the thickness of oxidation corrosion products based on the photoacoustic effect, which comprises the following steps: modulating laser irradiation of a specific frequency on the CRUD surface of a fuel cladding, monitoring the sound wave signals emitted by the CRUD surface by using a piezoelectric sensor, and establishing an online conversion model of the sound wave signals and the CRUD thickness, so that intuitive real-time thickness data can be obtained. The thickness of the CRUD is measured online and in situ without destroying the original environment of the CRUD, so that the measurement data can accurately reflect the real thickness of the CRUD in the growth environment. Through the method, the dynamic growth behavior characteristics of the CRUD thickness can be obtained, so that more accurate monitoring and guidance can be provided for the safe operation and fuel management of a reactor.

The invention relates to the technical field of electrical equipment testing, and particularly provides a space charge detection device and method based on optical measurement. The space charge detection device based on optical measurement comprises a sensing acquisition array which is uniformly distributed around detected equipment in the circumferential direction, full-surrounding detection of space charges is achieved, collaborative design of four optical detection technologies is adopted, multi-dimensional detection of the space charges is achieved through the complementary effect of Raman scattering, the photoacoustic effect, LIBS and the photoelectric effect, and the detection accuracy of the space charges is improved. The detection limitation of a single technology is made up; according to the space charge detection method based on optical measurement, a space-time synchronization-weight distribution-feature fusion algorithm and a signal-to-noise ratio-based adaptive weight distribution fusion algorithm are adopted, space-time synchronization calibration and Kalman filtering are combined, the problems of space-time inconsistency and random errors of multi-source data are solved, and the precision of data fusion is improved.

The present invention relates to a photo-acoustic spectroscopy gas cell designed for the identification of gases. The system comprises a gas chamber for containing a gas sample and a light receiving portion that receives excitation light capable of inducing a photo-acoustic effect in the contained gas. A cantilever is mounted at / within the gas chamber. The cantilever is specifically adapted with resonance characteristics that enable it to resonate in response to the photo-acoustic excitation generated within the gas cell. A measurement unit within the system is configured to analyze the response of the cantilever to the photo-acoustic effect, thereby determining the identification of the gas based on this response. This invention provides a precise and reliable way for gas analysis and identification

The application discloses a Fourier photoacoustic gas detection device and method, and belongs to the technical field of gas detection. In view of the limited anti-interference ability of a sound signal and the low detection sensitivity of an existing Fourier transform photoacoustic spectrum, a Fourier photoacoustic gas detection device is designed. A supercontinuum broadband light source is used as an excitation light source of a photoacoustic effect, the broadband light source is subjected to unified intensity modulation through an intensity modulation assembly and phase modulation through an interferometer assembly. After the broadband interference light emitted through double modulation interacts with gas molecules, wide-spectrum mixed sound waves are generated, a quartz tuning fork sound measurement assembly extracts resonance components and converts the resonance components into electrical signals. The generated electrical signals are sequentially subjected to processing through a signal amplification assembly, a phase-sensitive demodulation assembly and a Fourier transform assembly, and the processed signals are used for component discrimination and concentration inversion of a target gas.

Spectroscopic sensor for characterizing the absorption or determining the concentration of solid materials or liquid samples based on the photoacoustic effect, comprising - a device into which the liquid or solid sample to be analyzed is inserted or placed, - at least one laser in modulation mode to excite the material-specific molecules, - at least one sound transducer for detecting the sound pressure wave, - a device for detecting and processing the photoacoustic signal, characterized in that at least one sound transducer in the form of a quartz tuning fork (QTF) is used, the resonance frequency of which corresponds to the laser modulation frequency, that an acoustic resonator of a certain geometry, which is placed on the sample and has the same resonance frequency as the QTF, is used, that the laser modulation frequency corresponds to the resonance frequency of the resonator, and that the gas which fills the resonator shows as little or no absorption as possible in the wavelength range of the laser.

The invention provides a gas detection method and a gas detection system, and belongs to the technical field of spectral measurement, and the method comprises the following steps: carrying out collimation processing on a laser beam through a collimating lens; the wavelength of the laser beam is matched with the A band of the target gas; after the collimated laser beam penetrates through the gas in the medicine bottle to be detected, focusing the emergent laser beam to a quartz tuning fork by using a focusing lens; the quartz tuning fork converts the received optical signal into an electric signal; the absorption spectrum of the target gas is obtained along with the change of the wavelength of the laser, and then the concentration of the target gas in the medicine bottle to be detected is determined. The intensity of a traditional transmission absorption measurement mechanism is improved through the photoacoustic effect, limitation of medicine bottle refraction and internal shielding on long optical path construction is avoided, the requirements of the system for optical alignment precision and spatial layout are greatly reduced, and miniaturization and engineering applicability of equipment are achieved while high sensitivity is guaranteed.

The application discloses a kind of detection methods for internal defects of plastic package component, it is related to defect detection technical field, comprising the following steps: the pretreatment of plastic package component;Photoacoustic signal acquisition;Time-domain waveform extraction and analysis.The application uses the above-mentioned detection method for internal defects of plastic package component, measures the photoacoustic image of different plastic package components using photoacoustic detection system based on photoacoustic effect, extracts the time-domain waveform at different positions of plastic package component along the propagation direction of laser and ultrasonic wave, realizes the identification, positioning and defect type analysis of internal defects of plastic package component by analyzing the reflection peak position, shape, intensity characteristics of time-domain waveform, distinguishes the defect area and defect type in plastic package component using photoacoustic effect, provides a new means for nondestructive testing of internal defects of plastic package component, and has important significance for improving the reliability of plastic package component.

The invention relates to the technical field of VOC detection, in particular to an ultra-sensitive chemical equipment liquid volatile matter VOC detection system and method.The detection system comprises a sampling and enriching module used for conducting in-situ sampling and enriching low-concentration VOC at a detection point, improving the sample concentration and facilitating follow-up detection; the detection module is used for detecting the VOC concentration by adopting an excitation photoacoustic effect and eliminating background interference; the data processing and analyzing module is used for collecting the detection signal, analyzing and calculating the detection signal and outputting a VOC concentration value; and the intelligent calibration module is used for collecting environmental parameters, automatically calibrating the parameters of the detection system according to the change of the environmental parameters, and optimizing the detection range. According to the invention, rapid detection of a trace amount of leaked VOC can be effectively realized, the detection efficiency is improved, the leakage condition can be found in time, greater harm is avoided, and the production safety is guaranteed.

A system and method for protein detection are provided, configured to non-invasively identify proteins exhibiting specific structural conformations within a biological target. The system comprises a light source operable to irradiate the target at a predetermined pulse cycle, a sound detection device configured to capture acoustic signals generated via the photoacoustic effect, and an information processing unit that analyzes the detected acoustic signals to determine the presence or accumulation of a target protein. This technique facilitates early-stage detection of disease-associated proteins, such as amyloid-β and misfolded α-synuclein fibrils, without requiring complex imaging modalities or invasive biopsy procedures.

The application discloses a system for passive terminal communication, and belongs to the technical field of laser communication. The system comprises an optical-acoustic communication relay node module and a plurality of passive photoacoustic terminal modules. The optical-acoustic communication relay node module comprises a multi-channel encoder unit, an encoded laser unit, a listening laser unit, a beam control and tracking emission unit, a photoelectric detector unit and a decoding and communication exchange processing unit. The passive photoacoustic terminal module is composed of an optical-acoustic effect material. The application realizes bidirectional optical-acoustic communication between a plurality of passive terminals through the optical-acoustic communication relay node module. The application realizes networked, multi-user and real-time bidirectional communication between passive terminals while maintaining the advantages of no power supply and simple structure, solves the problems of multi-user access and relay forwarding in point-to-point optical-acoustic communication, and can be applied to the fields of non-electric environment, strong electromagnetic interference and secret communication.

The invention discloses a photoacoustic measurement method. The photoacoustic measurement method comprises the steps that a to-be-measured sample is measured based on the photoacoustic effect, an actual measurement spectrum representing the time domain change of the reflectivity of the to-be-measured sample is collected, the to-be-measured sample comprises N layers of thin films, and N is larger than or equal to 1; obtaining a target echo of each layer of film and a theoretical time value when the target echo reaches the upper surface of the to-be-tested sample; based on the theoretical time value of the target echo, obtaining a spectral characteristic peak search range of the corresponding layer of film; according to the actually measured spectrum and the spectral characteristic peak search range corresponding to each layer of thin film, acquiring an actually measured time value of the target echo of each layer of thin film reaching the upper surface of the sample to be measured layer by layer from the top layer of thin film; and according to the actually measured time value, establishing an equation set comprising to-be-measured parameters, and solving the equation set to determine the to-be-measured parameters which comprise the thickness of each layer of film of the to-be-measured sample. According to the technical scheme of the embodiment of the invention, the physical model can be simplified, and the film thickness measurement precision and calculation speed are improved.

The invention discloses application of a clofazimine suspension as an NIR-II fluorescent tracer and a dye tracer in the field of auxiliary diagnosis and treatment. The preparation has the advantages of good biological safety (suitable for mothers and infants), high sensitivity, high tissue penetrability, light stability and the like, and can reduce the inconvenience of clinical multiple administration and improve the compliance of patients. The NIR-II fluorescence imaging capability overcomes the limitation of the traditional imaging in strong light or deep tissue'black box 'environment, and is more suitable for intraoperative navigation. Meanwhile, due to the inherent red dyeing characteristic, the dye can be used as a lymph dye tracer. In combination with the NIR fluorescence effect and the photoacoustic effect of the clofazimine suspension, the intraoperative lymphatic cleaning can be assisted through a multi-mode combined tracing technology.

A device for measuring the power and wavelength of laser radiation via the photoacoustic effect, includes a cell containing at least one gas having an absorption line with a central wavelength λc, an electro-acoustic transducer arranged within the cell and suitable for generating a signal representative of the photoacoustic signal in the cell, means for processing the signal generated by the electro-acoustic transducer, wherein an estimate of the concentration of the one or more gases is stored, at least one laser source suitable for emitting, into the cell, laser radiation at a wavelength suitable for exciting at least one gas contained in the cell, the laser radiation having a wavelength that is variable in an oscillatory manner about an average wavelength λmoy at a modulation frequency (f1), such that an interaction between the laser radiation and at least one gas contained in the cell induces generation of a photoacoustic signal at a detection frequency of the electro-acoustic transducer, the cell being sealed by a membrane so as to be impermeable to the one or more gases contained in the cell and having an optical aperture transparent to the laser radiation, the processing means being configured to determine a variation in the phase Φ(t) of the photoacoustic signal based on the photoacoustic signal, the processing means being suitable for measuring the wavelength of the radiation based on the photoacoustic signal.

The application relates to the technical field of power equipment testing, and particularly provides a spatial charge detection device and method based on optical measurement. The spatial charge detection device based on optical measurement comprises a sensing and collecting array which is uniformly distributed around a measured device in a circumferential direction, full-surrounding detection of spatial charge is realized, and the four optical detection technologies are cooperatively designed; through the complementary effects of Raman scattering, photoacoustic effect, LIBS and photoelectric effect, multi-dimensional detection of spatial charge is realized, and the detection limitations of single technology are compensated; the spatial charge detection method based on optical measurement adopts time-space synchronization-weight distribution-feature fusion, an adaptive weight distribution fusion algorithm based on a signal-to-noise ratio, and combines time-space synchronization calibration and Kalman filtering, so that the time-space inconsistency and random error problems of multi-source data are solved, and the precision of data fusion is improved.

The invention relates to the technical field of optical detection, in particular to a rapid optical detection method and system after chip cutting, and the method comprises the following steps: applying frequency-modulated continuous thermal excitation to a cut wafer, and synchronously collecting a space-time coupling response matrix generated by thermal wave transmission and a photoacoustic effect on the surface of the wafer; identifying a deep subsurface crack extension track according to the thermal wave reflection coefficient distribution, and identifying a metal residue enrichment area according to the photoacoustic quality factor distribution; and performing spatial cross-correlation operation on the thermal wave reflection coefficient distribution and the photoacoustic quality factor distribution, constructing a defect composite index diagram, and dividing a risk interval according to a numerical gradient of the defect composite index diagram. According to the method, the problems that penetration is difficult and the structure continuity cannot be judged in a traditional surface optical image method are solved, and the non-contact property, the space resolution and the defect type recognition capability of a detection system are remarkably improved.

The present application relates to a kind of based on optical wavefront shaping and acoustic focusing to realize multimodal photoacoustic angiography method, comprising the following steps: carrying out regional positioning output optimal matching region coordinate, excitation optimal matching region coordinate photoacoustic effect;Focus on laser by wavefront shaping module;Through pulse generator excitation ultrasonic transducer generates ultrasonic pulse;Photoacoustic pressure wave signal and ultrasonic signal are in turn through amplification filter and analog-digital converter;The excited photoacoustic pressure wave and ultrasonic signal are in turn through acoustic focusing adjustment module enhancement;Digital enhancement photoacoustic signal and enhanced ultrasonic signal are carried out image reconstruction.The present application is based on optical wavefront shaping and acoustic focusing to realize multimodal photoacoustic angiography method, system, device, processor and its computer readable storage medium, improve laser energy utilization efficiency, reduce laser threshold, reduce equipment cost, improve deep tissue photoacoustic signal intensity and distribution uniformity.

The invention belongs to the technical field of chiral molecule detection, and provides a chiral molecule detection method and system based on a terahertz photoacoustic optical rotation spectrum. According to the method, pulse terahertz light is generated through a terahertz light source and modulated into circularly polarized light through polarization to irradiate a sample, ultrasonic waves generated after the sample is absorbed are detected through the photoacoustic effect, then sound pressure information is extracted, and the optical rotation is calculated. An optical rotation spectrum is obtained through wavelength and polarization scanning, and quantitative analysis of each chiral molecular component in a mixed solution is realized in combination with a linear spectrum unmixing model. The method disclosed by the invention can work at normal temperature, effectively inhibits water background interference, has high-sensitivity and high-specificity recognition and quantification capabilities on various chiral molecules in a complex system, and is suitable for the fields of biomedicine, pharmaceutical analysis, environmental monitoring and the like.

The invention belongs to the technical field of carbon dioxide concentration detection, and particularly relates to a multi-frequency modulation anti-interference carbon dioxide concentration detection method based on a photoacoustic effect. Comprising the following steps: S1, enabling infrared light with a certain wavelength to pass through CO2 gas to be detected; s2, periodically modulating the infrared heat source, and flashing according to pulses with different frequencies in the modulation stage; and S3, collecting a sound wave signal through a high-sensitivity MIC, extracting an MIC frequency spectrum amplitude characteristic value, and calculating the CO2 concentration according to a fitting formula of the calibration curve. A traditional fixed frequency modulation mode is broken through, and environment vibration noise is effectively separated through multi-frequency combination.