Deducing effective light transport parameters in optically thin systems

TL;DR

This paper provides a comprehensive Monte Carlo analysis of light transport in optically thin slabs, characterizing the ballistic-to-diffusive transition and offering tools for accurate parameter deduction from observable data.

Contribution

It introduces a detailed Monte Carlo study of light transport in thin slabs, validating diffusion theory predictions and providing a practical lookup table and software for parameter extraction.

Findings

Validated diffusion theory's prediction on spatial variance growth

Developed a lookup table for microscopic transport parameters

Provided a Monte Carlo software package for light transport analysis

Abstract

We present an extensive Monte Carlo study on light transport in optically thin slabs, addressing both axial and transverse propagation. We completely characterize the so-called ballistic-to-diffusive transition, notably in terms of the spatial variance of the transmitted/reflected profile. We test the validity of the prediction cast by diffusion theory, that the spatial variance should grow independently of absorption and, to a first approximation, of the sample thickness and refractive index contrast. Based on a large set of simulated data, we build a freely available look-up table routine allowing reliable and precise determination of the microscopic transport parameters starting from robust observables which are independent of absolute intensity measurements. We also present the Monte Carlo software package that was developed for the purpose of this study.