Acousto-Optic Beam Modulators and Deflectors Control Laser Beams in Many Applications.

by John Lekavich, Director, IntraAction

Acousto-Optics, the interaction of sound waves and light in a transparent medium, has proven an effective means of amplitude-modulating, deflecting, or shifting the optical frequency of laser light. When a transparent medium is subject to a stress, the optical refractive index of the medium changes. High frequency sound waves, launched into a transparent material via a piezoelectric transducer, will produce a periodic change in the refractive index of the material. In effect, the sound waves produce a grating capable of diffracting incident light. The amount of light diffracted is a function of the power in the acoustic wave. The seminal work on acousto- optic effects dates back to the 1920s and 1930s. The field came into its own in the 1960s after the development of the laser.

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Originally published Lasers & Application, April 1986