Entropic model for the optical properties of heterogeneous media: Validation on granular gold films near percolation

Abstract

A tool for the morphological analysis of heterogeneous media, namely, the normalized configuration entropy, is applied to the study of the specific morphology of granular metallic thin films. The proposed method allows us to determine the typical length (Formula presented) that is characteristic of the disorder of the image and we have developed an optical model for heterogeneous media, that is based on the partition of the actual image of the medium at the size (Formula presented) The model accounts well for the optical properties of thin granular gold films near the percolation threshold, where the classical effective-medium theories fail. The sensitivity of our model to local fluctuations in the morphology is tested on simulated images that are generated by using different algorithms. © 1998 The American Physical Society.