Differential light scattering: probing the sonoluminescence collapse

We have developed a light scattering technique based on differential measurement and polarization (differential light scattering, DLS) capable in principle of retrieving timing information with picosecond resolution without the need for fast electronics. DLS was applied to sonoluminescence, duplicating known results (sharp turnaround, self-similar collapse); the resolution was limited by intensity noise to about 0.5 ns. Preliminary evidence indicates a smooth turnaround on a less than approximately 0.5-ns time scale, and suggests the existence of subnanosecond features within a few nanoseconds of the turnaround.