We present a method for modeling focused Gaussian beams in turbid media. Compared to previous methods based on ray tracing, our method is simple and fast. Rather than sampling photon launch positions from the surface of the media, we directly sample launch positions from inside the sample volume using the probability distribution for the position that a ballistic photon will first interact with the tissue. The examples presented illustrate the importance of accounting for Gaussian beam optics when simulating a focused beam. Not doing so will give an artificially large irradiance at the beam waist position. Thermal models used to predict laser damage to tissue will predict temperature rises that are too large for samples containing the beam focus.
Cook, Patrick and Clark, Clifton D., "A Method for Coupling Monte Carlo Simulations of Photon Transport to Focused Gaussian Beam Propagation" (2020). 2020 SACAD Entrants. 16.