光声光谱技术应用于痕量气体浓度测量的研究进展

Research Development of the Application of Photoacoustic Spectroscopy in Measurement of Trace Gas Concentration

光声光谱技术作为实现痕量气体浓度高效率、高精度测量的重要气体传感技术,因其响应速度快、灵敏度高、选择性好等优点被广泛应用到大气环境检测、电力系统故障诊断、医疗健康诊断等领域当中。首先介绍了光声光谱技术痕量气体浓度测量的基本原理,对应用光声效应实现痕量气体浓度测量的机理进行了简要的描述,同时,介绍了基于光声光谱技术的典型痕量气体浓度测量装置的结构。其次,从光声信号强度的理论分析出发,引出国内外学者在光声光谱痕量气体浓度测量领域的研究热点,为了实现基于光声光谱技术的痕量气体浓度测量装置更强的抗干扰能力、更紧凑的结构、更低的检测下限、更高的检测灵敏度,国内外学者的研究重点可以总结为以下三点:(1)辐射光源的选取和设计,以实现更佳辐射光源的输出波长、更宽的调谐范围、更高的辐射光源输出功率。(2)更优秀的光声池设计,以实现更高效的声能量积聚、更紧凑的结构和更强的抗干扰能力。(3)声敏探测器的设计,以实现更高的声音灵敏度、更高的信噪比。详细介绍了基于光声光谱痕量气体浓度测量装置的三个核心元件:辐射光源,主要介绍了相干光源和非相干光源的应用研究进展;光声池,主要介绍了光声池的设计原则以及非共振式和共振式光声池的应用研究进展;微音器,主要介绍了电容式微音器、压电式微音器的应用研究进展,并对近期研究热点石英增强光声光谱技术进行简要的介绍。在介绍目前辐射光源、光声池、微音器应用研究进展的同时,分析了各元件的优势和需要解决的问题。最后,总结了光声光谱技术应用于痕量气体浓度测量领域装置存在的信噪比不高、结构复杂、检测灵敏度和检测下限易受混合气体之间的交叉干扰等问题,并且对未来测量装置中的三个核心元件:辐射光源、光声池、微音器的发展趋势进行了展望。

As an important gas sensing technology to achieve high-efficiency and high-precision measurement of trace gas concentrations,photoacoustic spectroscopy is widely used in atmospheric environment detection,power system fault diagnosis in medical and health diagnosis.This paper introduces the basic principle of trace gas concentration measurement by photoacoustic spectroscopy,and the mechanism of applying photoacoustic effect to realize trace gas concentration measurement is briefly described.At the same time,trace gases based on photoacoustic spectroscopy are introduced.Structure of the concentration measuring device.Secondly,starting from the theoretical analysis of photoacoustic signal intensity,the research hotspots of domestic and foreign scholars in photoacoustic spectroscopy trace gas concentration measurement are drawn.In order to realize the stronger anti-interference ability of the trace gas concentration measurement device based on photoacoustic spectroscopy technology,more compact structure,lower detection limit,and higher detection sensitivity,the research focus of domestic and foreign scholars can be summarized as the following three points:(1)Selection and design of radiation light source to achieve better output wavelength of radiation light source,Wider tuning range,higher output power of radiation source.(2)Better photoacoustic cell design to achieve more efficient acoustic energy accumulation,more compact structure and stronger antiinterference ability.(3)The design of the sound-sensitive detector to achieve higher sound sensitivity and signal-to-noise ratio.This paper introduces the three core components of the trace gas concentration measurement device based on photoacoustic spectroscopy in detail:radiation light source,mainly introduces the application research progress of coherent light source and incoherent light source;photoacoustic cell,mainly introduces the design principle of photoacoustic cell And the application research progress of non-resonant and resonant photoacoustic cells;Microphone,mainly introduces the application research progress of condenser microphone and piezoelectric microphone,and briefly introduces the recent research hot spot quartz enhanced photoacoustic spectroscopy technology's introduction.While introducing the current research progress in the application of radiation light sources,photoacoustic cells and microphones,the advantages of each component and the problems to be solved are analyzed.Finally,the problems of low signal-to-noise ratio,complex structure,detection sensitivity and lower detection limit are easily affected by cross-interference between mixed gases in the application of photoacoustic spectroscopy technology in trace gas concentration measurement.The development trend of the three core elements in the paper:radiation light source,photoacoustic cell,and microphone is prospected.