A new real-time surface profile measurement using a sinusoidal phase modulating interferometry

摘要

In this paper, a sinusoidal phase modulating interferometer has been proposed to realize real-time surface profile measurement. And its operation principle has been analyzed theoretically. By analyzing the interference signal through the signal processing circuit, the displacement of each point on the surface can be obtained. The experimental results by using this interferometer to measure a glass plate show the maximum root-mean-square is 5.2nm, and the displacement resolution is up to 5 × 10~(-3) nm.This method proposed in this paper avoids the complex phase demodulation by computer, has high measurement accuracy, and can be used in the noise circumstance.