Infrared mesh filters fabricated by electron-beam lithography

Capacitive and inductive infrared mesh filters have been fabricated using electron-beam lithography combined with a lift-off procedure. A single level of PMMA was used to create positive tone patterns while a two-level metal-on-polymer process was used to create negative tone patterns. Resonant structures consisting of arrays of crossed metal dipoles and arrays of crossed slots in otherwise continuous metal films have been fabricated that have linewidths less than 0.25 μm, and which exhibit bandstop and bandpass transmissive properties, respectively.