Optical transmission through subwavelength metallic gratings

Abstract

We present measurements of enhanced resonant transmission of infrared radiation through subwavelength metallic gratings made of rectangular grooves. This is achieved either by exciting a resonant waveguide mode in the cavities, or when the field is large enough above the groove, which is particulary satisfied close to surface plasmon excitation conditions at the air/metal interface. Moreover, we show that a model with plasmons on the incident side only explains this result very well.