Acoustic cavitation events during microsecond irradiation of aqueous solutions

The acoustic boundary conditions at the site of laser irradiation afiects the onset of cavitation when stress-conflned laser pulses are used. This study reports the thresholds for cavitation when the laser pulse length exceeds the stress conflnement time by a factor of eight. The cavitation threshold was deflned as the loss of an acoustic signal from the collapse of the cavitation bubble in room temperature dye solutions. The threshold temperature increase for cavitation at a free surface was 13§3 - C, at the tip of a 200"m flber in an aqueous solution was 17§2 - C, and at the interface of two acoustically matched boundary materials was 80§20 - C.