A Monte Carlo Study of the Transient Radiative Transfer Within the One-Dimensional Multi-Layered Slab

Short pulse lasers are considered a useful tool for material processing and diagnostics. Only recently, fundamental understanding of the pulse laser interactions with materials gained much attention. The analysis of the underlying process involves solving the transient radiative transfer equation, which is very challenging, and most prior work relied on the approximate models. In this paper, a time-dependent Monte Carlo method is used to study the transient radiative transfer within the nonhomogeneous absorbing and scattering media. The Monte Carlo results compared very well with the accurate deterministic models and such comparisons have been lacking in many prior Monte Carlo studies. The problem of interest has one-dimensional multi-layered slab geometry. Two different media are examined; a two-layer slab with different absorption and scattering coefficients in each layer; and a three-layer medium with different scattering albedo in the mid-layer. The temporal spreads of the transmittance and reflectance of a pulsed, collimated incident beam are obtained. The photon propagation across the interface and the resultant output radiative signatures due to the layered properties are discussed in detail.