The response of nanostructured surfaces in the near field

The authors of ref. 1 state that their numerical calculation of the transmission intensity dependence of very simple subwavelength planar structures in a silver film agrees well with an earlier-developed model, but both model and numerical simulation show significant disagreement with the experimental results of ref. 3. The authors speculate that the silver surfaces of the subwavelength structures used in ref. 3 were contaminated by an 11 nm overlayer of silver sulphide, because such a layer would bring the reported experimental results and their calculations into better agreement