<title>Laser Hydrophone</title>

Abstract

The light output of He-Ne lasers has been found to be sensitive to acoustic pressures applied to the lasers. It is theorized that the variation in the laser output is due to the following pressure effects: (1) microscopic mechanical deformations, both linear and angular and (2) pressure changes of the He-Ne gas. A one mw laser in air responds to sound waves with fair sensitivity from 80 Hz to 10 kHz and as a hydrophone with somewhat better sensitivity from 500 Hz to 50 kHz.