Encoded binary diffractive element to form hyper-geometric laser beams

Abstract

A binary diffractive optical element (1500 pixels × 1500 pixels, diameter 4.5 mm) is designed by partial encoding and fabricated by direct electron beam writing in SiO2. Two conjugate hyper-geometric laser modes are generated using the fabricated element. The root-mean-square transverse intensity deviation of the experimental from theoretical diffraction pattern, determined within a circle of radius 1 mm, is below 13%.