Total resonant absorption of light by plasmons on the nanoporous surface of a metal

We have calculated light absorption spectra of planar metal surfaces with a two-dimensional lattice of spherical nanovoids just beneath the surface. It is shown that nearly total absorption of light occurs at the plasma resonance in a void lattice in the visible range when the intervoid spacing and the void deepening into the metal are thinner than the skin depth, which ensures optimal coupling of void plasmons to external light. We conclude that the absorption and local-field properties of this type of nanoporous metal surface can be effectively tuned through nanoengineering of the spherical pores and that they constitute a very attractive system for various applications in future submicron light technology. (C) 2005 Pleiades Publishing, Inc.