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Photoacoustic Point Source

2001; American Physical Society; Volume: 86; Issue: 16 Linguagem: Inglês

10.1103/physrevlett.86.3550

1092-0145

Irio G. Calasso, Walter Craig, Gerald J. Diebold,

Ultrasound and Cavitation Phenomena

We investigate the photoacoustic effect generated by heat deposition at a point in space in an inviscid fluid. Delta-function and long Gaussian optical pulses are used as sources in the wave equation for the displacement potential to determine the fluid motion. The linear sound-generation mechanism gives bipolar photoacoustic waves, whereas the nonlinear mechanism produces asymmetric tripolar waves. The salient features of the photoacoustic point source are that rapid heat deposition and nonlinear thermal expansion dominate the production of ultrasound.