Resonant transmission enhancement at one-dimensional metal gratings

An analysis of phenomena leading to high transmission at a one-dimensional metal grating is presented. It is shown that high resonant transmission can be obtained either for thick or thin gratings for a wide range of filling factors and that the origins of the enhanced transmission are different in each case. We analyse the optical response of structures with subwavelength slits and of various thicknesses. The role of different pure (dielectric cavity modes, surface plasmon polaritons) and coupled resonances on the enhanced transmission is presented.