Single Bubble Sonoluminescence.    Rachel Ruch, San Francisco State University, Harold Metcalf and John Noé, Laser Teaching Center, SUNY at Stony Brook.

Single bubble sonoluminescence (SBSL) is the process of creating flashes of light using ultrasonic sound waves. It is a phenomenon of considerable current interest due to the extremely high temperatures reached (above 10,000 K) and the mysteries still shrouding the details of the mechanism.

SBSL is brought about by injecting a gas bubble into a flask of liquid, typically degassed water, that is vibrating at its fundamental resonance of $\sim$26 kHz. Two piezoelectric transducers (PZTs) on opposite sides of the flask create the necessary intense standing wave. The bubble is attracted to the vibrational node at the center of the flask, where it repeatedly expands and contracts due to the changing sound pressure in the surrounding liquid. The rapid collapse of the bubble causes it to emit photons which appear to peak in the ultra-violet.

Achieving SBSL requires $\sim$1000 peak volts AC across the PZTs. This high voltage can be attained with the use of a series LRC tuned circuit in which the PZT acts as an electrical capacitor. Most of our efforts in this project were concentrated on constructing and tuning this circuit and developing a suitable amplifier to drive it. While we were also able to repeatedly capture bubbles in the intense sound field, we did not attempt to observe the SBSL light in the limited time available for this.

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

Rachel Ruch August-2000