Optical transparency of mesoporous metals

We examine the optical properties of metals containing a periodic arrangeme nt of nonoverlapping spherical mesopores, empty or filled with a dielectric material. We show that a slab of such a porous metal transmits light over regions of frequency determined by the dielectric constant of the cavities and the fractional volume occupied by them, with an efficiency, which is ma ny orders of magnitude higher than predicted by standard aperture theory. A lso, the system absorbs light efficiently over the said regions of frequenc y unlike the homogeneous metal. (C) 2001 Elsevier Science Ltd. All rights r eserved.