Abstract: An acoustical imaging system wherein an acoustic beam projected through a transmission medium is modified (scattered) by a subject therein and impinges upon one side of an acousto-optic interface. The other side of this interface is made concave and mirror-surfaced to reflect an illuminating laser beam. The acousto-optic interface is "composite," being fabricated from an epoxy matrix with a multitude of tiny spherular capsules, or "microballons" distributed therein to thereby match the acoustic impedance of this interface to that of the transmission medium.