Theoretical noise-limited sensitivity of classical interferometry

Abstract

The signal-to-noise ratios for the path-stabilized, the active-heterodyne, the Sag, and the Fabry-Perot interferometers are calculated for cases in which dynamic surface displacements are detected. Expressions for the minimum-detectable displacements are given for the sensitivity limit of each interferometer. It is found that the ultimate sensitivities of the interferometers considered are nearly equal for similar conditions of use. Sensitivity values are shown to be about 10−15 m Hz−1/2 for systems that use typical laboratory instruments.