Transmission enhancement through nanoscale metallic slit arrays from the visible to mid-infrared

Abstract

In this paper, we systematically investigate the transmission enhancement through nanoscale metallic slit arrays in the wavelength range from visible to mid-infrared. The far-field transmittance of the periodic structure is calculated using the rigorous coupled-wave analysis (RCWA). The electromagnetic field distribution in the near-field regime is analyzed to elucidate three mechanisms for transmission enhancement. Depending on the spectral region, the enhanced transmission can be attributed to Wood's anomaly, cavity resonance, and the effective-medium behavior. The effects of grating/slit geometry, polarization, and the plane-of-incidence orientation on the radiation transmission are also examined.