THERMALLY LAUNCHED PHOTOACOUSTIC WAVES

Photoacoustic waves call be generated by submicron sized particles tha t absorb radiation and transmit heat to a surrounding fluid. When the thermal expansion coefficient of the absorbing body is small, a photoa coustic effect is not produced until heat diffuses into the surroundin g fluid. The time evolution of the acoustic wave produced by a suspens ion of particles can be monitored using the transient grating techniqu e. Experiments are reported for a reverse micelle solution.