Spectrum of synchronous picosecond sonoluminescence

Abstract

Measurements of the spectrum of sonoluminescence (SL) indicate that it extends from above 700 nm to below 190 nm. Furthermore the spectral density increases as photon energy increases. Calibration of the spectrum indicates that it accurately matches the tail of a 25 000-K blackbody. At lower ambient temperatures (≤10 °C) the spectral weight shifts even further into the UV so that SL appears to match the spectral tail of a 100 000-K blackbody. In order to gain further insight as to the physical origin of the spectrum, the air bubbles are replaced with argon bubbles and the effects of various solutes are studied. [Work supported by the US DOE Division of Advanced Energy Projects.]