SINUSOIDAL PHASE MODULATING FIZEAU INTERFEROMETER

Sinusoidal phase modulating interferometry is possible with Fizeau interferometers. The sinusoidal phase modulation is easily produced by vibrating the reference plate glass in a Fizeau interferometer. Since we can measure the amplitude and phase of the phase modulation with the interferometer itself, the exact phase modulation is obtained. The usefulness of the sinusoidal phase modulating Fizeau interferometer is made clear through surface profile measurements of 80-mm diam plate glasses and integrated circuit wafers and movement measurements of integrated circuit wafers. © 1990 Optical Society of America.