Diffraction properties of double-layer rectangular phase gratings

Abstract

We theoretically present diffraction properties of double-layer rectangular phase gratings (DLRPGs). Computer simulations show that these DLRPGs can realize several functions such as optical filtering, optical switching, optical amplitude modulating, beam splitting with variable output beam numbers and wavelength division multiplexing, and so on. As a test of the above diffraction properties, we fabricate a set of DLRPGs in a double-layer light-sensitive material by the contact printing method. Based on the DLRPGs of the material, a single beam splitter with experimental results of splitting of an incident beam into 2, 3 or 5 output beams and of higher than 64% total diffraction efficiency are realized when the incident angle of the readout beam is tuned during the reading process.