Two quantum cascade laser spectrum-based multicomponent gas simultaneous detection device and method

Abstract

The present invention relates to the technical field of laser spectrum detection and gas detection, and in particular relates to a two quantum cascade laser spectrum-based multicomponent gas simultaneous detection device and method. An arbitrary waveform function generator outputs a periodic signal which only superposes high-frequency modulation signals in any half period to be used as a laser current signal, a room temperature continuous mode mid-infrared quantum cascade laser is driven by a current control unit, the laser emits a laser signal, the laser signal passes sequentially through a focusing collimating three-dimensional adjustment system, a first mirror, a sample absorption pool and a off-axis parabolic mirror to be reflected to a first detector, the first detector passes the laser signal through a data acquisition unit to convert into an electrical signal and transmit to a computer, and information of the gas to be measured can be obtained by analysis and processing of the electrical signal by the computer. The devices simultaneously utilizes two spectrums for gas detection, and has the advantages of high detection sensitivity, high detection accuracy, no need of external standard gas calibration, simple optical path adjustment, fast response, and stability, and the like.

Description

technical field [0001] The invention relates to the technical fields of laser spectrum detection and gas detection, in particular to a multi-component gas simultaneous detection device and method based on two quantum cascade laser spectra. Background technique [0002] Traditional gas composition detection methods mainly include chemical methods and optical methods. Chemical methods usually require pretreatment of the analyte, the process is complex, time-consuming, easy to destroy the original state of the sample and produce secondary pollutants; optical spectroscopy has the advantages of non-contact, non-destructive, strong selectivity and fast response. Real-time in-situ continuous analysis can be realized, making it widely used in the fields of atmospheric environment monitoring, industrial process control, combustion component detection and respiratory gas diagnosis. [0003] Commonly used optical spectroscopy methods include direct absorption spectroscopy and waveleng...

AI Technical Summary

Problems solved by technology

The former discloses a trace gas detection device and method based on direct absorption spectroscopy of mid-infrared quantum cascade lasers. This method uses pulsed quantum cascade lasers as a light source and uses direct absorption spectroscopy alone. and optical noise interference, limited sensitivity, gas concentration inversion method reliability and low measurement accuracy; the latter discloses a trace gas detection method and device based on mid-infrared spectroscopy with a long optical path open optical path combined with wavelength modulation technology , this method uses a continuous quantum cascade laser as a light source and uses wavelength modulation spectroscopy alone, which has the disadvantages of requiring frequent calibration of additional standard gas, and the pressure broadening effect under high pressure reduces sensitivity and reliability.

[0006] In practical application, the above two traditional methods are not ideal enough.

The present invention intends to use both direct absorption spectroscopy and wavelength modulation spectroscopy to detect gases. This method can overcome the defects that exist when only one spectral method is used for gas detection. Research on the detection of single-component gas or multi-component gas based on the above two methods of quantum cascade laser spectroscopy

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