Photo-thermo-acoustic (PTA) effect of a multilayer composite material with periodic micro-nano structures (PMNS): Modeling, simulation and experiment

The photo-thermo-acoustic (PTA) effect of a three-layer composite material whose surface is fabricated with many periodic micro-nano structures (PMNS) is investigated in this paper. The material is composed of a silicon substrate, a thermal insulation layer of polyimide, and a light-absorbing layer of aluminum nanoaggregates. We propose a method for analyzing the PTA effect based on the idea of finite element meshing. The PTA conversion processes including the photo-thermal conversion and the thermal-acoustic conversion are quantitatively simulated. The influence of the geometric parameters of the PMNS on the intensity and space distribution of the sound field is analyzed both by simulation and experiment. The results show that fabricating PMNS on composite materials can significantly enhance the PTA effect. And the finite element analyzing method proposed in this paper can correctly describe and predict the PTA effect of composite materials with two-dimensional PMNS. It is also applicable for analyzing the PTA effects of other similar materials or structures.