Broadband Extraordinary Optical Transmission Through Gold Diamond-Shaped Nanohole Arrays

Extraordinary optical transmission (EOT) is widely accepted as a resonant phenomenon. However, the nonresonant EOT phenomenon of subwavelength metallic nanohole arrays on a metallic thin film is significant for harvesting of broadband light, confining optical power in small area, and enhancing local electric field. To achieve nonresonant EOT, a novel paradigm structure comprising periodic diamond-shaped nanohole arrays engraved on a thin gold film is proposed. The transmission properties of the diamond-shaped nanohole arrays are calculated using the finite-element method. Results show that this paradigm structure facilitates a broadband and enhanced transmission in the infrared region. In addition, the effects of incident polarization and structural parameters on the transmission property are also studied.