High-speed infrared frequency-modulated laser spectroscopy gas detection system and method based on quantum cascade laser

Abstract

The invention relates to a quantum cascade laser-based high-speed infrared frequency modulation laser spectrum gas detection system and method. The system comprises a quantum cascade laser spectrum scanning module, a high-speed frequency modulation module, a synchronization module, a gas multi-returning cavity and a frequency modulation spectrum acquisition module. On the basis of a conventional gas detection system, a distributed feedback quantum cascade laser is used, and a mid-infrared laser is utilized to generate intensity-modulated modulated light for irradiating and pulsating an emergent end face of the quantum cascade laser, thus realizing all-optical modulation on the quantum cascade laser; control and quantitative detection on a gas sample are completed by the gas multi-returning cavity; an all-optical modulation gas absorption spectrum is collected by a high-speed mid-infrared detector, a high-speed lock-in amplifier, a high-speed signal collection card and a computer, thus realizing high-speed high-accuracy gas detection. The high-speed infrared frequency modulation laser spectrum gas detection system can be applied to a high-sensitivity infrared laser spectrum technology and trace gas detection.

Description

technical field [0001] The invention belongs to the technical field of infrared laser spectroscopy, and in particular relates to a high-speed infrared frequency-modulated laser spectroscopy gas detection system and method based on quantum cascade lasers. It is used in high-speed, high-sensitivity infrared laser spectroscopy and trace gas detection applications. Background technique [0002] Among the existing gas detection technologies, the laser spectroscopy gas detection method has the characteristics of high sensitivity, and the quantum cascade laser has the advantages of narrow line width, high power, and can work at room temperature, especially the infrared quantum cascade laser, whose output wavelength scans The range lies in the fingerprint spectral region of the gas, which is a huge advantage especially for trace gas detection. At present, the direct absorption spectrum detection method based on quantum cascade lasers can achieve fast detection, but its absorption s...

AI Technical Summary

Problems solved by technology

At present, the direct absorption spectrum detection method based on quantum cascade lasers can achieve fast detection, but its absorption signal is in the low frequency range, and the signal-to-noise ratio is low; The signal-to-noise ratio is improved, and the detection limit of the system is improved. However, due to the slow scanning method of ramp current, the detection time is relatively long, generally on the order of milliseconds

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