INFRARED-ABSORPTION OF GRANULAR METAL-FILMS IN THE PERCOLATION RANGE

Experimental optical absorption of gold granular films near the percol ation threshold are compared with a two dimensional simulation using a real space renormalization procedure. It is some times asserted that the optical properties around the percolation cannot be described by a n effective dielectric function, but we obtain good agreement between the simulations and the experimental data. According to this approach, the IR absorption is attributed to the surface plasmon modes broadene d toward IR wavelengths due to the fractal nature of the clusters.