Multiphysics Simulation of Low Frequency Terahertz Induced Thermoacoustic Signal Characteristics

Terahertz technology is rapidly developing and playing an important role in the fields of material identification, biomedicine, and communication. However, the strong absorption of terahertz energy in water has limited the development of terahertz technology to some extent. In fact, the strong absorption of terahertz energy in water causes the generation of terahertz photoacoustic (THz-OA) signal, and the propagation depth of THz-OA signal is much longer than the propagation depth of terahertz waves in water. In this paper, we construct the geometric model and use the finite element method to simulate and study the multi-physics effect of low frequency terahertz wave pulse width on the time interval of THz-OA signal. The results show that the time interval of the THz-OA signal changes synchronously with the terahertz pulse width, and the time interval of the two peaks of the THz-OA signal is always equal to the terahertz pulse width.