Laser beam machined free-standing terahertz metamaterials

The use of laser ablation of a thin metal film, which allows for rapid prototyping of various free-standing terahertz devices, is reported. The technique will provide a simple way to fabricate devices without complicated photolithography procedures. This could be a solution for a multitude of new optical elements for the terahertz regime. The fabricated samples are free-standing films and, hence, benefit from the absence of a supporting dielectric substrate, which could induce dispersion, losses or alter the reflection properties. Three devices are demonstrated: a wire-grid polariser, a polarisation converter and bandpass filters, and their performance is characterised.