Displacement Measuring System using a Fizeau Interferometer

Abstract

A displacement measuring system has been developed using a Fizeau interferometer without polarizers. The system is simple in construction and compact. A reference mirror with a λ/8 step on one side was used instead of polarizers. A High resolution of 0.2 μm was obtained with a semiconductor laser of 780 nm. The wavelength of the peak laser oscillation was calibrated by measuring the temperature of the case to improve accuracy. The errors of the measurements are discussed in detail and are estimated to be ± (0.20 μm+0.75%). The system was used to measure the displacement of a pulse stage, and the characteristics of the stage were measured. The measuring system proves to be highly accurate in displacement measurement.