Surface relief diffraction gratings fabricated in ZnSe by frequency doubled Nd:YAG laser micromachining

A novel and rapid laser ablation method for the fabrication of diffractive optical elements (DOE) in ZnSe that takes advantage of the relatively low intensity damage threshold of the material is presented. The structures were characterized in terms of their shape and diffraction efficiency at normal incidence under 10.6 μm radiation for TE and TM polarizations. Sample surface polishing as well as the possible effect of the melted zone and structural modification of the material around the ablated region on the power transmission capability of the grating are also discussed.