A Multiple-phase-mask Model Constrained by the Spatial Power Spectrum Density

Comparing to the renowned Monte Carlo (MC) simulation, multiple-phase-mask models are attracting more and more interests recently because of its capability to simulate coherent light propagation in turbid medium. In a conventional random phase mask model presented by Schott et al., many phase masks are evenly spaced in sequence, light scattering is assumed to occur only at the masks. Thus, each mask represents a scattering event, and the interval between adjacent ones is determined by the mean free path (MFP). The phase distribution of each mask is constraint by the scattering phase function in an iterative phase retrieval algorithm. However, the intensity diffusion profile of light inside this model could not agree with MC simulation and the memory effect range of the model is much smaller than experiment. In order to solve these problems, we modified the conventional multiple-phase-mask model by integrating ballistic and multiple scattering light into consideration through spatial power spectrum density. In detail, we concentrate all scattering events happened in an interval onto the back mask and make their spatial power spectrum densities equal. Different from the conventional model, the interval is not fixed. For the new model, the memory effect range in simulation is proved to be consistent with experiment. Here, we provide more evidences for the validity of this model in simulation of scattering media. How interval distance and anisotropy factor g affect the phase mask is investigated to deepen our understanding. A comparison to the angular spectrum model of light inside scattering media is also presented.