Analysis of characteristics of acoustic waves induced by triangular laser pulses

To investigate the influence of the waveform of laser pulses on the characteristics of photoacoustic pulses, based on the theory of thermoelastic mechanism for generation of acoustic waves, the characteristics of acoustic waves induced by triangular laser pulses were analyzed by means of theoretical derivation and numerical simulation. Firstly, the theory of thermoelastic mechanism for generation of a plane acoustic source by laser pulses in liquid was elaborated firstly. The analytic expressions of the acoustic pulses induced by laser pulses at the constraint margin and free margin were deduced when the laser waveform was triangular, and the sections of the photoacoustic pulses were obtained through emulation. Secondly, the waveform of the photoacoustic pulse was simulated. Finally, the photoacoustic conversion efficiency was deduced and the influencing factors were analyzed. And then the conversion efficiency at rigid margin and free margin were solved and compared. The obtained results can supply theoretical instruction for the engineering application of the technique of laser generation of acoustic waves.