Thanks to the available ultra-wide wavelength range compared with broadband laser sources, the use of blackbody radiators in photoacoustic spectroscopy features the simultaneous detection of multiple gas species in the presence of cross-interfering absorption lines. The major problem associated with broadband incoherent sources is less power and less stable intensity per wavenumber than lasers and leads to limited gas detection sensitivity. In this paper, the detectivity of a broadband double optical path differential photoacoustic system was enhanced with the development of dimension-optimized high-responsivity T-resonators for simultaneous multiple trace gas detection. Enhanced Q-factor and external noise suppression level constitute dual criteria for the optimization of T-resonators. Three digital signal processing algorithms were separately investigated which further improved gas dectectability. The capability of the multiple–trace-gas detection framework was verified by measuring CO₂, C₂H₂ and H₂O simultaneously. The spectral results processed by a wavelet denoising algorithm present the best performance in terms of background noise suppression and spectral feature fidelity. [Q2.2] With the absorption enhancement of the optimized T-cells and background suppression of the wavelet denoising algorithm, a broadband differential photoacoustic system was achieved with only a 30 mW globar source and normalized noise equivalent absorption coefficient value of 4.1 × 10⁻¹⁰ W·cm⁻¹·Hz^−1/2 which is two orders of magnitude improvement over the original T-cell-based photoacoustic configuration. The noise equivalent detection limits were found to be 223 ppbv for CO₂, 625 ppbv for C₂H₂ and 865 ppbv for H₂O, respectively.

由于与宽带激光源相比可用的超宽波长范围，在光声光谱中使用黑体辐射器的特点是在存在交叉干扰吸收线的情况下同时检测多种气体。与宽带非相干光源相关的主要问题是与激光相比，每波数的功率更低，强度更不稳定，并导致气体检测灵敏度有限。在本文中，宽带双光路差分光声系统的探测能力随着用于同时多痕量气体探测的尺寸优化的高响应率 T 型谐振器的发展而得到提高。增强的 Q 因子和外部噪声抑制水平构成了优化 T 型谐振器的双重标准。分别研究了三种数字信号处理算法，进一步提高了气体可检测性。通过测量 CO 验证了多痕量气体检测框架的能力₂、C ₂ H ₂和H ₂ O同时进行。小波去噪算法处理的频谱结果在背景噪声抑制和频谱特征保真度方面表现最佳。[ Q2.2 ]通过优化 T 细胞的吸收增强和小波去噪算法的背景抑制，仅使用 30 mW 全局光源和归一化噪声等效吸收系数值为 4.1 × 10 ^-就实现了宽带差分光声系统^{- 10} W·cm ^-1 ·Hz ^-1/2这比原始的基于 T 细胞的光声配置提高了两个数量级。发现噪声等效检测限对于 CO ₂为 223 ppbv ，对于 C ₂ H ₂为 625 ppbv，对于 H ₂ O为 865 ppbv 。