SINGLE-BUBBLE SONOLUMINESCENCE. Fernando Enrique Ziegler, The University of Texas at Austin, John Noé and Harold Metcalf, Laser Teaching Center, SUNY at Stony Brook.

Single bubble sonoluminescence (SBSL) is the process of creating light from the gas in a tiny bubble suspended inside a flask of water by means of intense ultrasonic sound waves. Under ideal conditions of dissolved gas and sound field a single micron-sized bubble will undergo sustained contractions and expansions in step with the sound pressure fluctuations for many minutes, emitting very brief (50 picoseconds) flashes of mostly blue and ultraviolet light every 35 microseconds. We used the standard SBSL setup in which the intense 25 kHz sound field is created with two piezo-electric transducers attached on opposite sides of a standard 100 mL spherical flask and a third smaller transducer picks up the interaction of the sound waves and the bubble for display on an oscilloscope. After some experiments with the degassing procedure, sonoluminescence was achieved, although the light output seemed to be less than reported by some others. Our efforts were then directed at improving and fine tuning the setup to increase the light intensity. For example, the shape and frequency of the acoustical resonance was studied as a function of the precise volume of water in the flask and the degree of degassing. Work is also under way to observe the sonoluminescence light with a sensitive photomultiplier tube.

This study was supported by NSF Grant No. PHY99-12312.