Aperture apodization on regular gratings with variable transmission in the zero diffraction order

Abstract

A new principle of aperture apodization for imaging and transform optical systems with controlled splitting of the output light beam into spatially selected diffraction orders and deflection of all higher orders beyond the operating region is proposed and investigated. Implementation of the principle is based on the use of regular gratings whose transmission coefficient in the useful zero diffraction order changes slowly from cell to cell, and excess light is coupled to higher orders and is screened with a field stop. To test the proposed principle, we designed, experimentally fabricated, and investigated an optical refracting telescope equipped with an apodizing filter with a binary amplitude circular structure and having the intensity of the first spurious diffraction peak of the point spread function 10 times lower than that in the embodiment without filter.