Semi-analytical model of acoustic-wave generation by a laser line pulse in an optically absorptive isotropic cylinder

Abstract

Semi-analytical model for calculating acoustic response to a line-focused laser pulse in an optically absorptive isotropic cylinder is proposed and implemented. It is assumed that the laser input is absorbed over the volume and thus creates a radially distributed thermoelastic source. Closed-form solution is obtained in the Fourier domain. Two inverse Fourier transforms in frequency and circumferential wave number yield the sought waveforms of acoustic response in the time-space domain. Numerical simulation is compared to the calculation based on a surface dipole source. The two signals have essentially different shapes of the wave-arrival peaks when the optical penetration is large enough.