Photoacoustic spectroscopy employs acoustic resonators for signal amplification. Resonators are usually closed, however, in some applications, open resonators are preferred. The opening deteriorates the photoacoustic signal hence reducing the sensitivity of the photoacoustic measurement. We present two new approaches for simulating the photoacoustic signal in open resonators using finite element modelling. The approaches are based on the amplitude mode expansion model and the viscothermal model with the opening modelled using perfectly matched layers and the boundary element method respectively. Additionally, the performance of the viscothermal model using perfectly matched layers for simulating open resonators is extended to the ultrasound region. The simulation results are verified by comparing them to photoacoustic measurements. The approaches provide an accurate basis for designing and optimizing open resonators with high sensitivity.

光声光谱法使用声谐振器进行信号放大。谐振器通常是封闭的，但是在某些应用中，开放谐振器是首选。该开口使光声信号劣化，因此降低了光声测量的灵敏度。我们提出了两种使用有限元建模来模拟开放式谐振器中的光声信号的新方法。这些方法基于振幅模式展开模型和粘热模型，分别使用完美匹配的层和边界元方法对开口进行建模。另外，使用完美匹配的层来模拟开放式谐振器的粘热模型的性能扩展到了超声区域。通过将仿真结果与光声测量值进行比较，可以验证仿真结果。