Photoacoustic (PA) cell is an important component for PA spectroscopic trace gas measurement. However, its high responsivity towards light absorption in trace gases can be compromised to the background baseline generated from optical windows of the cell. In this research, a 2-D physical model considers double effects (thermoelasticity and thermoacoustics) was proposed to reveal the generation mechanism of the background spurious signal caused by absorption of the windows in a rectangular PA cell. The authentic PA signal due to gas absorption was modeled to obtain the signal-to-noise ratio (SNR) dependence of the best optical parameters. Beam collimation and dimensional conditions with respect to the SNR were discussed in detail, which was verified using an accurate finite element method. This proposed model exhibits flexibility and simplicity on straightforward sensitivity analysis in a PA cell and can avoid use of massive numerical calculation.

光声 (PA) 池是 PA 光谱痕量气体测量的重要组成部分。然而，它对痕量气体中光吸收的高响应性可能会受到电池光学窗口产生的背景基线的影响。在这项研究中，提出了一种考虑双重效应（热弹性和热声）的二维物理模型，以揭示矩形 PA 单元中由窗口吸收引起的背景杂散信号的产生机制。对由气体吸收引起的真实 PA 信号进行建模，以获得最佳光学参数的信噪比 (SNR) 依赖性。详细讨论了与 SNR 相关的光束准直和尺寸条件，并使用精确的有限元方法对其进行了验证。