Laser Interferometric Sensing Techniques for Very Small Displacements-With Applications to Gravitational Radiation Detectors

Abstract

In this paper we discuss the use of laser interferometry with resonant optical cavities to sense very small displacements of suspended test masses in a gravitational radiation detector. In particular we describe and discuss the performance of a prototype interferometer currently under development, which has high finesse cavities, 10-m long, and is illuminated by highly frequency-stabilized light from an argon laser. A displacement sensitivity close to 10-N,sup>16 m/√Hz at kHz frequencies, limited by photon noise in the detected light, is achieved.