INTERFEROMETER UTILIZING A TUNABLE LASER OR SIMILAR FREQUENCY VARIABLE WAVE ENERGY GENERATOR

摘要

An interferometer having a frequency tunable laser generator for reflecting laser light from a movable mirror to provide an optical interference fringe pattern. A servo circuit, that includes detectors for receiving the optic fringe pattern and providing output signals whenever any displacement of the movable mirror causes the fringes to begin moving, automatically adjusts the frequency of the laser light signal to maintain the fringes in a fixed position. The direction and magnitude of the frequency variation of the laser signal required to hold the fringes in a fixed position is measured to determine the direction and magnitude of mirror displacement.