Thermally launched photoacoustic waves

Photoacoustic waves can be generated by submicron sized particles that absorb radiation and transmit heat to a surrounding fluid. When the thermal expansion coefficient of the absorbing body is small, a photoacoustic effect is not produced until heat diffuses into the surrounding fluid. The time evolution of the acoustic wave produced by a suspension of particles can be monitored using the transient grating technique. Experiments are reported for a reverse micelle solution