Tuning of Plasmonic Resonances in the Near Infrared Spectrum Using a Double Coaxial Aperture Array

Plasmonic filters are excellent candidates for spectral filters in the near infrared spectrum. Such filters require only a single nanoscale thickness perforated metal film that can be tailored to tune the location of the transmission maximum. Here, we demonstrate using computational methods a double coaxial aperture array (DAA) in a hexagonal geometry that can be tuned to produce plasmon resonances accompanied by strong transmission in the near-infrared spectrum and at telecommunication wavelengths with a peak wavelength insensitive to angle of incidence. The DAA consists of two concentric annular apertures and radial distance between the two apertures is varied to tune the resonant wavelength. The presented geometry finds potential applications in modulators for telecommunication, spectroscopy, solar cells, high-resolution CMOS image sensors, chemical sensors, and biosensors.