Midinfrared doping-tunable extraordinary transmission from sub-wavelength Gratings

Abstract

The authors demonstrate doping-tunable extraordinary transmission from subwavelength apertures in a periodic two-dimensional metallic grating deposited upon n-doped GaAs. By varying the doping of the underlying GaAs epilayer, they demonstrate wavelength tunability of ∼23cm−1 or approximately 0.15μm. The authors have achieved transmission peaks as narrow as 18cm−1 with such gratings, which suggests that devices based on midinfrared extraordinary transmission gratings could be used in external cavity structures for quantum cascade lasers, or as tunable filters or modulators for midinfrared applications.