One-Step fabrication of a high-efficiency flat-top beam shaper

Abstract

A compact beam shaper is required to efficiently convert coherent Gaussian beam into a flat-top beam for applications such as optical processing, laser radar, laser microfabrication, and laser scanning. A number of techniques for laser beam shaping have been developed so far [1-3]. Directly truncating the Gaussian beam with an aperture and weighting the Gaussian beam with a neutral density filter of proper amplitude transmittance profile have very poor energy efficiency. Binary shaper based on interlaced diffraction gratings suffers from its limited diffraction efficiency. Diffractive optics beam shaper fabricated by computer-generated hologram technique, by only changing the propagation phase patterns prior to diffraction focusing, is an effective beam shaper method.