Imaging light transport at the femtosecond scale: a walk on the wild side of diffusion

In this thesis work we investigated light transport in scattering media from a spatio-temporal perspective. To this purpose, we have designed and developed an experimental optical-gating setup and a new Monte Carlo software library focused on the measurement and simulation of spatio-temporal evolution of light transport down to a sub-picosecond resolution. The unique properties of both these tools allowed us to unveil an array of unexplored aspects of light propagation occurring in the extremely general plane-parallel slab geometry, which are of relevance both for application and fundamental purposes due to their asymptotic nature. Indeed, time-domain techniques are commonly considered to offer the most straightforward and powerful characterization capabilities, in that they allow to selectively address different transport regimes and directly observe their evolution. However, as we extensively demonstrate, combining the temporal information with wide-field spatial imaging capabilities offers a significant improvement, unveiling a set of irreducible information that could not be accessed from separate spatial and temporal characterizations.