Phase shift measuring apparatus utilizing optical meterodyne techniques

摘要

A phase shift measuring apparatus for detecting a phase shift of a light wave passing through an object to be measured, including: supplying device for supplying first and second light waves having different frequencies; optical device for directing the first light wave toward the object and combining the first light wave passing through the object and the second light wave to obtain a composite light wave; detecting device for receiving the composite light wave and detecting a measured beat signal; and measuring device for comprising the measured beat signal with a predetermined reference beat signal to measure a phase shift of the first light wave. A gradient index, a thickness distribution, and the like of an object can be obtained from the measured phase shift.