Patent ID: 7652773

Claim:
A system for detecting acousto-photonic emissions in optically turbid media, comprising: a sound source for generating an ultrasonic wave for propagation through an optically turbid medium; a light source for generating a signal light beam for transmission through the optically turbid medium, and for generating a reference light beam, wherein the signal light beam is phase modulated in the presence of the ultrasonic wave within an interaction region of the optically turbid medium; a photo-detector including a photo-refractive crystal for receiving the phase modulated signal light beam and the reference light beam, and for converting the phase modulated signal light beam to an intensity modulated signal light beam by interference of the phase modulated signal light beam and the reference light beam within the photo-refractive crystal, the intensity modulated signal light beam having a DC component; and a signal analyzer for analyzing the DC component of the intensity modulated signal light beam to obtain a measure of a magnitude of a mean phase shift induced by the ultrasonic wave on the signal light beam within the interaction region of the optically turbid medium, and for analyzing at least one change in the magnitude of the mean phase shift, the at least one change in the magnitude of the mean phase shift being indicative of an object or an abnormality at the interaction region of the optically turbid medium.