Enhancement of trace gas detectability using photoacoustic spectroscopy requires the effective suppression of strong background noise for practical applications. An upgraded infrared broadband trace gas detection configuration was investigated based on a Fourier transform infrared (FTIR) spectrometer equipped with specially designed T-resonators and simultaneous differential optical and photoacoustic measurement capabilities. By using acetylene and local air as appropriate samples, the detectivity of the differential photoacoustic mode was demonstrated to be far better than the pure optical approach both theoretically and experimentally, due to the effectiveness of light-correlated coherent noise suppression of non-intrinsic optical baseline signals. The wavelet domain denoising algorithm with the optimized parameters was introduced in detail to greatly improve the signal-to-noise ratio by denoising the incoherent ambient interference with respect to the differential photoacoustic measurement. The results showed enhancement of sensitivity to acetylene from 5 ppmv (original differential mode) to 806 ppbv, a fivefold improvement. With the suppression of background noise accomplished by the optimized wavelet domain denoising algorithm, the broadband differential photoacoustic trace gas detection was shown to be an effective approach for trace gas detection.

使用光声光谱法提高痕量气体可检测性要求在实际应用中有效抑制强背景噪声。基于配备特殊设计的T谐振器并同时具有差分光学和光声测量功能的傅立叶变换红外（FTIR）光谱仪，研究了升级后的红外宽带痕量气体检测配置。通过使用乙炔和局部空气作为适当的样品，由于非本征光学基线的光相关相干噪声抑制的有效性，在理论上和实验上都证明了差分光声模式的检测能力远优于纯光学方法。信号。详细介绍了具有优化参数的小波域降噪算法，通过针对差分光声测量消除不相干的环境干扰，大大提高了信噪比。结果表明，对乙炔的敏感性从5 ppmv（原始差模）提高到806 ppbv，提高了五倍。通过优化的小波域降噪算法实现背景噪声的抑制，宽带差分光声痕量气体检测是一种有效的痕量气体检测方法。结果表明，对乙炔的敏感性从5 ppmv（原始差模）提高到806 ppbv，提高了五倍。通过优化的小波域降噪算法实现背景噪声的抑制，宽带差分光声痕量气体检测是一种有效的痕量气体检测方法。结果表明，对乙炔的敏感性从5 ppmv（原始差模）提高到806 ppbv，提高了五倍。通过优化的小波域降噪算法实现背景噪声的抑制，宽带差分光声痕量气体检测是一种有效的痕量气体检测方法。