Quantitative characterization of turbid media using pressure contrast acousto-optic imaging

An acousto-optic imaging technique suitable for the local and quantitative determination of subsurface optical properties in turbid media is presented. Acousto-optic signals elicited by ultrasound pulses at two different peak pressures in turbid media are detected by using photorefractive-crystal-based interferometry. The ratio of the measured signals, once calibrated for a particular set of pressure pulses, is found to give a direct measure of the reduced scattering coefficient of the interaction region between the light and sound. Measurements of the reduced scattering coefficient of inclusions buried in diffuse tissue phantoms are demonstrated.