Measurement of cavitation noise and bubble oscillation using acoustooptic detection scheme

An optical method for detecting cavitation noise and bubble oscillation is presented. The acoustooptic effect of acoustic pressure and optical effect of bubble oscillation were utilized. In order to observe bubble oscillations, an attempt was made to separate the optical effect of bubble oscillations from the acoustooptic effect of acoustic pressure. A single sensing beam system detects both acoustic pressure and bubble oscillation, whereas a double sensing beam system cancels acoustooptic effect of acoustic pressure effectively allowing bubble oscillations to be detected separately. It has been demonstrated by experiment that the double sensing beam system decreases the acoustic pressure effect by more than 30 dB so that the frequency spectrum of bubble oscillation can be observed.