Scalable full-wave simulation of coherent light propagation through biological tissue

Simulating coherent light propagation through mm or cm scale biological tissues would aid in studying phenomena such as optical memory effects, optical focussing via wavefront shaping, and image formation in techniques such as optical coherence tomography. This is challenging however, because existing simulation methods are either not complete enough to model the underlying deterministic scattering and interference processes accurately, or are too computationally intensive to model large enough volumes of tissue. To address this challenge, we use the “T-matrix” method to simulate coherent light propagation through a discrete particle model of tissue. Using this method, we find that the speckle pattern produced by a plane wave incident on a 100 μm thick tissue-like medium can be simulated in about a tenth of the time needed for a pseudospectral time-domain simulation. Moreover, by varying the plane wave's incident angle, the angular memory effect can be observed and the the angular memory correlation range measured. By demonstrating the method's efficiency and its applicability to studying a coherent phenomenon in a tissue like medium, this work could pave the way to modelling a range of coherent optical phenomena in deep tissue using this technique.