Reflective shearing point diffraction interferometer

Abstract

A novel point diffraction interferometer with reflective shearing optical structure is developed. The substrate of interferometer has an angle with optical axis, and the incident converging spherical wavefront will be reflected by the front and rear surfaces of the substrate, respectively. Then, an interferogram with carrier frequency is obtained. Using Fourier transform algorithm, the wavefront can be retrieved from one single interferogram. In this article, the intensity distribution formulas of interferogram are derived, and the system error and the major parameters of interferometer are also discussed. The new design with compact structure and high resolution is contrast adjustable and suitable for dynamic wavefront measurement.

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