RESOLVING SONOLUMINESCENCE PULSE-WIDTH WITH TIME-CORRELATED SINGLE-PHOTON COUNTING

The width of the short light pulses emitted from a single air bubble t rapped in a resonant sound field in degassed water has been measured f or the first time using time-correlated single photon counting. The pu lse width at room temperature increases from about 60 ps at low gas co ncentrations and low driving pressures to more than 250 ps at high gas concentrations and driving pressures at the upper sonoluminescence th reshold. The pulse shape is nearly Gaussian and is identical in the re d and UV part of the spectrum.