Apparatus and method for measuring characteristics of light

Abstract

An optical phase characteristic measuring apparatus includes a harmonic generator for generating a harmonic wave from a fundamental wave of output light from a light source; a beam splitter for splitting a fundamental-wave component of the output light and a harmonic component; a sample disposed in one of optical paths along which light beams from the beam splitter propagate; a unit that is composed of a signal generator and a mirror and is adapted to modulate the length of one of the optical paths; an optical mixer for mixing the light beams containing the fundamental-wave component and the harmonic component; an optical separator for separating light output from the optical mixer into a fundamental-wave component and a harmonic component; a first optical detector for detecting a fundamental-wave component of an output from the optical separator; a second optical detector for detecting a harmonic component of the output from the optical separator; and a phase detector for detecting the phase difference between AC signals output from the two optical detectors. An optical amplitude/phase characteristic measuring apparatus has a similar structure but includes two light sources, a sum-frequency generator, and other related circuits.