Abstract: A system and method for detecting a sound originating from a body and enhancing signal-to-noise ratio with respect to noise originated outside the body is disclosed. The system comprises a light source for producing a quasi-monochromatic, spatially-coherent light beam; and interferometer for interfering alight beam originated from the source, incident upon the body and reflected from it, with a reference beam, which also originates from the light source; and a detector for detecting changes caused by motion of a least one interference fringe across the detector, and for generation a corresponding electric signal.