Phase-shifting point-diffraction interferometer developed by using the electro-optic effect in ferroelectric crystals

A novel and simple phase-shifting point-diffraction interferometer using a z-cut lithium niobate wafer is proposed. The pinhole is realized by an optical lithography process, aluminum deposition, and subsequent liftoff on the surface of the wafer. The phase shifting is obtained by inducing the electro-optic effect along the z crystal axis. We demonstrate experimentally the possibility of retrieving an aberrated wavefront.