Measurement and control of subangstrom mirror displacement by acousto-optical technique

Abstract
Control of laser mirror spacing and angular orientation is important for laser frequency and mode stability. A wave front sensor that employs acousto-optic modulation and optical heterodyning has been applied in conjunction with a servo-control loop to control mirror motion. The measurement and control of subangstrom mirror displacements are possible using this system. Experimental results are presented that indicate closed-loop control of mirror displacement to within 0.06 nm.