Optical tuning of extraordinary optical transmission through a metallic hole array using azobenzene dye-doped nematic liquid crystal

Abstract

Optical tuning of extraordinary optical transmission (EOT) through a metallic hole array is achieved using an azobenzene dye-doped nematic liquid crystal. The liquid crystal is aligned homeotropically on the hole array and is sandwiched by a counter substrate placed at a distance of approximately 1 µm from the hole array. Upon UV irradiation, the azobenzene dye photo-isomerizes from the trans conformation to the cis conformation and disturbs the liquid crystalline order, causing a decrease in the effective refractive index. The tuning range achieved was 80 nm, and corresponded to a refractive index shift of 0.086. Optical tuning of EOT properties is potentially important for future all-optical processing of signals.