A Michelson Interferometer for Relative Phase Locking of Optical Beams

Abstract

A Michelson-type interferometer is built to dynamically lock the optical phase difference between the two-arm laser beams. The phase difference is tunable and allowed for continuous adjustments nearly by 160^°. Under the best locking condition, a relative phase stability better than 0.1^° is achieved starting from the original phase jitter of 10 to 15^°. The interferometer is made by simply adding a pair of Brewster windows in one arm of the conventional setup, yet it provides much robust phase locking. It is readily applicable for optical lattice construction and nondestructive phase contrast imaging of ultracold atoms.