全光谱傅里叶变换光声光谱的气体检测研究

Full-Spectrum Fourier Transform Photoacoustic Spectroscopy for Gas Sensing

摘要:

提出了一种基于差分共振光声池的傅里叶变换光声光谱技术，并系统地评估了其在宽带检测和多气体同步检测方面的性能表现。通过引入干涉仪的相位调制和机械斩波器的强度调制，实现了对宽带光源的统一调制，从而实现了傅里叶变换光谱与谐振光声探测模块的高效结合。实验采用卤钨灯热光源与碳棒热光源对甲烷、 乙炔等单组分气体及其多组分混合气体进行检测，实现了在 1~20 μm 波段范围内的宽带响应。结果表明，傅里叶变换光声光谱技术融合了傅里叶变换光谱和光声光谱的优势，具备宽光谱响应、高分辨率、并行复用、无背景干扰及无波长选择的特性，可支持气体宽带检测和多气体同步检测，展现出全光谱检测的潜力，广泛适用于从可见光到红外甚至太赫兹波段的检测应用。

Abstract:

This paper presents a Fourier transform photoacoustic spectroscopy （FT-PAS） system based on a differential resonant photoacoustic cell （DPAC）， and systematically evaluates its performance for broadband and simultaneous multi-gas detection. Uniform modulation of a broadband light source is achieved through phase modulation via an interferometer and intensity modulation via a mechanical chopper， enabling efficient integration of Fourier transform spectroscopy with a resonant photoacoustic detection module. Broadband detection of singlecomponent gases， including methane and acetylene， as well as their multi-component mixtures， across the 1-20 μm spectral range was carried out using a tungsten halogen lamp and a carbon globar thermal source. The results demonstrate that FT-PAS， combining the strengths of both Fourier transform and photoacoustic spectroscopy， exhibits characteristics such as broad spectral response， high resolution， parallel multiplexing， zero background interference， and wavelength independence. These attributes enable its use for broadband and simultaneous multi-gas detection， with potential applications spanning the full spectrum from the visible to the infrared region， and even extending into the terahertz range.