One-mode model and Airy-like formulae for one-dimensional metallic gratings

We present a semi-analytical model that quantitatively predicts the transmission, the absorption and the resonance locations of one-dimensional lamellar metallic gratings with subwavelength slit apertures. The model relies on the fact that subwavelength apertures perforated in metallic films behave like monomode waveguides and provide Airy-like formulae for the transmission and reflection coefficients. Limitations are outlined for too shallow grating depths.