Transmission of light by a single subwavelength cylindrical hole in metallic films

This letter presents theory and finite-difference time-domain calculations in excellent agreement with experiments for the transmission of a single subwavelength cylindrical hole in Ag metallic films. The authors discuss the very large enhancement in transmission by single holes in terms of surface plasmons at the interface of the hole. These are similar to the surface plasmons in metallic cylinders reported by Economou and co-workers [Phys. Rev. B 10, 3038 (1974); 24, 6908 (1981)]. The peak structures observed in experiments with arrays of holes are a consequence of interference of the beams transmitted by each hole and are determined by the hole periodicities. The role of the arrays in enhancement of the transmission due to surface plasmon polaritons appears to be marginal.