Wire grid polarisers can be used in order to polarise unpolarised molecular laser radiation, or to attenuate the emission of a polarised laser. LASER COMPONENTS offers ruled wire grid polarisers on CaF2 and ZnSe substrates, and holographic wire grid polarisers on CaF2, ZnSe, BaF2, KRS-5 and Ge substrates. This range of available substrate materials collectively covers a wavelength region from 2.5 to 30 microns, providing parts suitable for most common applications.
Ruled wire grid polarisers are produced by directly ruling precisely spaced grooves into the substrate material. The resulting well defined peaks are then deposited with aluminium, forming an array of parallel ‘wires’. Ruled wire grid polarisers are suitable for use in higher power laser applications.
The holographic counterpart is produced by projecting coherent laser beams onto a photo-resist coated substrate to produce a precise pattern of equally spaced grooves. Once processed, the resist has a sinusoidal surface relief profile which is then aluminium coated at an oblique angle to create an array of parallel conductors.
This production technique allows for use of a number of substrate materials that would not be possible with a ruling technique. ZnSe and Ge wire grid polarisers are anti-reflection coated in order to maximise transmission efficiencies.