Characterization of Acoustic Sources by Optical Feedback Interferometry

Sound can be described as the propagation of pressure variations in compressible media that involves compression and expansion and induces a change in the density of the medium. This change in acoustic pressure as it induces a change of the refractive index can be measured by optical methods, the most recent being the optical feedback interferometry. With this technique, a laser diode is beaming on a reflective surface thus creating a cavity where the acoustic wave propagates. This paper presents anovel experimental technique to measure radiation pattern of acoustic sources based on optical feedback interferometry in a laser diode.