Holey Random Walks: Optics of Heterogeneous Turbid Composites

TL;DR

This paper develops a probabilistic theory for light transport in heterogeneous turbid media with non-scattering regions, enabling analytical predictions of key optical properties validated by simulations.

Contribution

It introduces a new theoretical framework for analyzing light diffusion in media with heterogeneity, including non-scattering regions, advancing understanding of complex optical systems.

Findings

Analytical predictions match Monte Carlo simulations

Step correlations significantly affect transport properties

Differences between bounded and unbounded systems are characterized

Abstract

We present a probabilistic theory of random walks in turbid media with non-scattering regions. It is shown that important characteristics such as diffusion constants, average step lengths, crossing statistics and void spacings can be analytically predicted. The theory is validated using Monte Carlo simulations of light transport in heterogeneous systems in the form of random sphere packings, and good agreement is found. The role of step correlations is discussed, and differences between unbounded and bounded systems are investigated. Our results are relevant to the optics of heterogeneous systems in general, and represent an important step forward in the understanding of media with strong (fractal) heterogeneity in particular.