CN-122016678-A - Photo-thermal bomb spectrum gas detection device and method based on incoherent fixed spectrum excitation

CN122016678ACN 122016678 ACN122016678 ACN 122016678ACN-122016678-A

Abstract

The invention relates to a photoelastic spectrum gas detection device based on incoherent fixed spectrum excitation, which comprises an incoherent light source module, an optical shaping module, a gas absorption module, a sampling module and a signal amplifying and demodulating module, wherein the incoherent light source module is sequentially arranged and used for generating incoherent light with controllable power and light intensity modulation depth, the optical shaping module is used for shaping the incoherent light beam and effectively coupling the incoherent light into the sampling module, a gas accommodating cavity used for storing gas to be detected is arranged in the gas absorption module, the sampling module is used for periodically thermally depositing the gas to be detected formed by the sampling module after the incoherent light is absorbed by the gas to be detected, the sampling module is used for collecting thermoelastic stress generated by the periodic thermally depositing and converting the thermoelastic stress into an electric signal, and the signal amplifying and demodulating module is used for extracting and demodulating the electric signal acquired by the sampling module. The incoherent fixed spectrum light source has more uniform light field distribution, and a wide spectrum output can cover a plurality of absorption peaks within a fixed spectrum range and is insensitive to wavelength drift.

Inventors

ZHENG HUADAN
LIN HAOYANG
GUO TUAN

Assignees

暨南大学

Dates

Publication Date: 20260512
Application Date: 20260127

Claims (10)

1. A photoelastic spectrum gas detection device based on incoherent fixed spectrum excitation is characterized in that, the photoelastic spectrum gas detection device based on incoherent fixed spectrum excitation comprises the following components in sequence: The incoherent light source module is used for generating incoherent light with controllable power and light intensity modulation depth; the optical shaping module is used for shaping the incoherent light beam and effectively coupling the incoherent light into the sampling module; The gas absorption module is internally provided with a gas accommodating cavity for storing gas to be detected, the shaped irrelevant light enters the gas accommodating cavity, and the gas to be detected which is pre-arranged in the gas accommodating cavity absorbs the light energy of the irrelevant light; the sampling module is used for collecting thermoelastic stress generated by the periodic thermal deposition and converting the thermoelastic stress into an electric signal; and the signal amplifying and demodulating module is used for extracting, amplifying and demodulating the electric signals acquired by the sampling module.
2. The photothermal elastance spectrum gas detection apparatus based on incoherent fixed spectrum excitation according to claim 1, wherein, The incoherent light source module comprises a function generator, a driver and an incoherent fixed spectrum light source which are connected in sequence, The function generator is used for outputting a periodic modulation signal, the driver converts the modulation signal output by the function generator into a stable current so as to drive an incoherent fixed spectrum light source, and the incoherent fixed spectrum light source generates broadband light with a fixed spectrum under the driving of the output current of the driver.
3. The photothermal elastance spectrum gas detection apparatus based on incoherent fixed spectrum excitation according to claim 2, wherein, The incoherent fixed spectrum light source is a broadband LED or a super-radiation light-emitting diode SLED.
4. The photothermal elastance spectrum gas detection apparatus based on incoherent fixed spectrum excitation according to claim 1, wherein, The optical shaping module comprises a collimating mirror or an optical collimating system.
5. The photothermal elastance spectrum gas detection apparatus based on incoherent fixed spectrum excitation according to claim 1, wherein, The gas accommodating cavity of the gas absorbing module is a gas absorbing tank or an open sampling area, The gas absorption tank or the open sampling area is internally provided with a detected gas.
6. The photothermal elastance spectrum gas detection apparatus based on incoherent fixed spectrum excitation according to claim 1, wherein, The sampling module is a photo-thermal detector or a pyroelectric detector.
7. The photothermal elastance spectrum gas detection apparatus based on incoherent fixed spectrum excitation according to claim 1, wherein, The sampling module is a piezoelectric tuning fork, and the piezoelectric tuning fork receives thermal elastic stress and converts the thermal elastic stress into an electric signal.
8. The photothermal elastance spectrum gas detection apparatus based on incoherent fixed spectrum excitation according to claim 1, wherein, The signal amplifying and demodulating module comprises a pre-amplifier and a phase-locked amplifier.
9. The photothermal elastance spectrum gas detection apparatus based on incoherent fixed spectrum excitation according to claim 1, wherein, The system also comprises a data processing unit which is used for controlling the flow of the photo-thermal bomb spectrum gas detection device based on incoherent fixed spectrum excitation and collecting the output data of the signal amplifying and demodulating module, The output end of the data processing unit is connected with the input end of the function generator of the uncorrelated light source module, and the data processing unit is used for controlling the output of the function generator; The input end of the data processing unit is electrically connected with the output of the signal amplifying and demodulating module, and the data processing unit collects the amplified electric signals for analysis and processing to obtain the physical characteristics of the gas to be detected.
10. The control method of the photo-thermal bomb spectrum gas detection device based on incoherent fixed spectrum excitation is applied to the photo-thermal bomb spectrum gas detection device based on incoherent fixed spectrum excitation as claimed in any one of claims 1 to 9, and is characterized in that the control method of the photo-thermal bomb spectrum gas detection device based on incoherent fixed spectrum excitation comprises the following steps: S100, under the control of a data processing unit, a function generator of an incoherent light source module outputs a periodic modulation signal, and a driver converts the modulation signal into stable current to drive an incoherent fixed spectrum light source, wherein the incoherent fixed spectrum light source generates broadband light with a fixed spectrum; s200, an optical shaping module shapes incoherent light beams and effectively couples the incoherent light beams into a sampling module; s300, the gas to be detected of the gas accommodating cavity absorbs light energy of irrelevant light; S400, after broadband light is absorbed in the gas to be detected, the light energy is deposited on a sampling module in a periodic mode according to a modulation rhythm, so that periodic temperature rise and thermoelastic stress are induced, and a piezoelectric charge signal changing along with time is generated; s500, the piezoelectric charge signal is amplified by a pre-amplifier of the signal amplifying and demodulating module, and then a stable thermoelastic characteristic signal is extracted by a phase-locked amplifier under the reference of the frequency of the function generator and is sent to the data processing unit for processing.

Description

Photo-thermal bomb spectrum gas detection device and method based on incoherent fixed spectrum excitation Technical Field The invention relates to the technical field of optical gas detection and photoelectric sensing, in particular to a photoelastic spectrum gas detection device and method based on incoherent fixed spectrum excitation. Background The optical gas detection has the advantages of high sensitivity, strong selectivity, high response speed and the like, and is applied to the fields of environmental protection monitoring, industrial leakage early warning, medical diagnosis, public safety and the like for a long time. Among the optical detection methods, photo-thermal elastography (Light-Induced Thermoelastic Spectroscopy, LITES) has been attracting attention as a novel detection technology that has been rapidly developed in recent years, because of the advantages of no need of an acoustic resonator, compact structure, and strong adaptability to the environment. The core principle is that the incident light is absorbed by the gas to generate periodic optical power change, and the change causes periodic temperature fluctuation on the surface of the sensitive material, thereby causing thermoelastic stress disturbance and further being converted into a measurable electric signal through an electromechanical conversion mechanism. In conventional photoelastic spectroscopy schemes, a coherent laser such as a distributed feedback laser (DFB), a Quantum Cascade Laser (QCL), etc. is typically used as a light source, with a narrow linewidth output that exactly matches a specific absorption line. However, high coherence and high directivity of laser easily introduce speckle noise and local spot hot spots, and strict requirements are put on beam alignment, temperature stability and driving current, resulting in complex system structure, higher cost and sensitivity to environmental disturbance. Disclosure of Invention The invention provides a photoelastic spectrum gas detection device and method based on incoherent fixed spectrum excitation, and aims to at least solve one of the technical problems in the prior art. The technical scheme of the invention is a photo-thermal bomb spectrum gas detection device based on incoherent fixed spectrum excitation, which comprises the following components in sequence: The incoherent light source module is used for generating incoherent light with controllable power and light intensity modulation depth; the optical shaping module is used for shaping the incoherent light beam and effectively coupling the incoherent light into the sampling module; The gas absorption module is internally provided with a gas accommodating cavity for storing gas to be detected, the shaped irrelevant light enters the gas accommodating cavity, and the gas to be detected which is pre-arranged in the gas accommodating cavity absorbs the light energy of the irrelevant light; the sampling module is used for collecting thermoelastic stress generated by the periodic thermal deposition and converting the thermoelastic stress into an electric signal; and the signal amplifying and demodulating module is used for extracting, amplifying and demodulating the electric signals acquired by the sampling module. Further, the uncorrelated light source module comprises a function generator, a driver and an incoherent fixed spectrum light source which are connected in sequence, The function generator is used for outputting a periodic modulation signal, the driver converts the modulation signal output by the function generator into a stable current so as to drive an incoherent fixed spectrum light source, and the incoherent fixed spectrum light source generates broadband light with a fixed spectrum under the driving of the output current of the driver. Further, the incoherent fixed spectrum light source is a broadband LED or a super-radiation light-emitting diode SLED. Further, the optical shaping module comprises a collimating mirror or an optical collimating system. Further, the gas accommodating cavity of the gas absorbing module is a gas absorbing tank or an open sampling area, The gas absorption tank or the open sampling area is internally provided with a detected gas. Further, the sampling module is a photo-thermal detector or a pyroelectric detector. Further, the sampling module is a piezoelectric tuning fork, and the piezoelectric tuning fork receives thermal elastic stress and converts the thermal elastic stress into an electric signal. Further, the signal amplifying and demodulating module comprises a pre-amplifier and a phase-locked amplifier. Further comprises a data processing unit which is used for controlling the flow of the photo-thermal bomb spectrum gas detection device based on incoherent fixed spectrum excitation and collecting the output data of the signal amplifying and demodulating module, The output end of the data processing unit is connected with the input end of the function generator of the