SPECTRA OF SINGLE-BUBBLE SONOLUMINESCENCE IN WATER AND GLYCERIN-WATERMIXTURES

A single gas bubble, acoustically levitated in a standing-wave field a nd oscillating under the action of that field, can emit pulses of blue -white light with duration less than 50 ps. Measurements of the spectr um of this picosecond sonoluminescence with a scanning monochrometer a re reported for air bubbles levitated in water and in glycerin-water m ixtures. While the spectrum has been reported previously by others for air bubbles in water, the spectrum for air bubbles in water-glycerin mixtures has not. Expected emission lines from glycerin were conspicuo usly absent, suggesting a different mechanism for light production in single-bubble sonoluminescence. Other conclusions are the spectrum for air bubbles in water is consistent with that previously reported, the radiated energy decreases as the glycerin concentration increases, an d the peak of the spectrum appears to shift to longer wavelengths for the water-glycerin mixtures.