Binary diffractive mask as a beam-shaping element for direct application in large-angle gray scale element fabrication

Abstract

The capability of binary gray scale masks in generating beams with a desired lateral intensity profile is extensively studied in order to fabricate large-angle microprisms. Using a recently introduced technique, some samples based on pulsewidth modulation are designed, so that the pulsewidth is changed with different linear rates from a completely clear to a fully dark slit, which results in a different number of gray steps. Then, the influence of the rate on turning an incident plane wave into beams with different specially linear lateral intensity distributions was studied by simulation, experiment, and fabrication of a large-angle microprism. Further, it was shown that the width of the first slit and the increment of gray level have an effective impact on the slope and smoothness of the generated linear intensity profile across the beam. Simulation results are completely verified by experimental data and the fabricated linear gray scale element.