INTERFEROMETERS FOR MEASURING CHANGES IN OPTICAL BEAM DIRECTION

摘要

Apparatus for measuring angular changes in the direction of travel of a light beam comprising at least one beam shearing assembly 30 for separating, preferably orthogonally polarized, components of the light beam and introducing a lateral shear between them. An analyzer 40 operates on the components to provide them with a common polarization state. A lens 46 focuses the commonly polarized components of the light beam to a spot in a detector plane, and a detector 60 operates to generate an electrical signal having a phase that varies in accordance with the angular change of the light beam in at least one plane. Electronic means 70 receive the electrical signal, determines the phase therefrom, and converts the phase to the angular change in the direction of travel of the light beam12.