Superior free‐standing meshes for use as infrared Fabry–Perot elements made with a new photolithographic technique

A photolithographic technique for fabrication of very smooth and highly uniform metallic, free‐standing, inductive meshes, is described. The fabrication process was developed in order to produce highly reflective, low‐loss Fabry–Perot étalon elements for use in the infrared spectral region. The measured rms smoothness of the grids is typically ≤30 Å. Because of their nickel core, the mechanical strength of the grids is such that they can be easily stretched flat on stainless‐steel rings.