ASA 126th Meeting Denver 1993 October 4-8

3aPA4. Synchronous picosecond sonoluminescence.

Bradley P. Barber Robert Hiller Ritva Lofstedt Seth Putterman

Phys. Dept., Univ. of California, Los Angeles, CA 90024

A strong sound field can (1) trap a bubble of gas at a velocity node, (2) maintain the bubble against diffusion, and (3) at sufficient intensity cause it to emit flashes of light that have intensities over 30 mW and widths less than 50 ps. The flashes are emitted in a clocklike fashion with a jitter that is also less than 50 ps. The spectral intensity of the sonoluminescence (SL) increases into the ultraviolet. The mechanism for this effect is still unknown but light scattering experiments have resolved the bubble motion---radius versus time---on a scale of nanoseconds and indicate that the light is emitted by a supersonic collapse. The emitted intensity is a strong function of ambient temperature and varies by a factor of 200 between 1 and 40 C. Light scattering measurements of temperature-dependent SL therefore provide data that can critically test any proposed theory such as imploding shock waves [C. C. Wu and P. H. Roberts, Phys. Rev. Lett. (May 1993)]. [Work supported by the US DOE Division of Advanced Energy Projects, R. L. is supported by an AT&T fellowship.]