Study on four-step computer-generated hologram with same diffraction efficiency of the zeroth and first order

Abstract

A type of computer-generated hologram (CGH) with 4-step microstructure is designed based on diffraction theory. Results show that this CGH has almost the same diffraction efficiency at zeroth diffractive order and positive first diffractive order, which are 38.51% and 38.04%, respectively, and the intensity of these two beams is 76.55% of incident beam. This type of 4-step CGH can be used in an off-axis convex aspherical mirror interferometric system with double CGHs, while the signal-to-noise ratio (SNR) of the interferogram is high enough.