Fabrication of Metallic Far-Infrared Filters

A far-infrared filter is fabricated by creating metallic squares on a dielectric substrate. This capacitive metallic filter is fabricated using direct write laser ablation consisting of a femtosecond laser in combination with a high numerical aperture objective. A representative capacitive filter is fabricated on soda-lime glass substrate with a period of 100 mu m and separation width of 30 mu m. A partial capacitive filter was also fabricated on a thin film polyethylene substrate with similar dimensions.