Optimization of wiregrid polarizers for CO2 laser

Metallic gratings (wiregrids) can function as efficient polarizers with high extinction ratio. The polarizing effect is due to the fact that these gratings act as a metal for the polarization parallel to the lines, reflecting most of it and absorbing the rest, and as a dielectric for the polarization perpendicular to the lines, transmitting profusely. A short semi-intuitive explanation of this behavior is given. A wiregrid polarizer for the CO₂ lasers is designed and then the parameters of the grating that can be varied - according to the specifics of the available lithographic procedure - are optimized. The sets of optimum polarizer parameters together with the corresponding performances are listed and discussed from a practical point of view.