Finite difference time domain analysis of diffusion equations with nonuniform grids for time-resolved reflectance of an optical pulse in three-dimensional scattering medium

摘要

An integral form of diffusion equations and their finite difference time domain (FDTD) analysis have been formulated. The analysis is extended to FDTD analysis with nonuniform grids in three-dimensional (3-D) scattering medium. It has been confirmed that 600 time steps in calculation sequences of the time-resolved reflectance for 3-D medium 80 x 80 x 30 mm(3) in volume is completed within 4 seconds by utilizing 23 and 43 mm(3) nonuniform cubic grids, when a conventional personal computer with 3 GHz CPU clock is used. The conditions for keeping numerical accuracies comparable to those in 2(3) mm(3) uniform grids are made clear. The proposed analysis greatly reduces time to run and memory space in 3-D scattering medium numerical analysis. (c) 2005 The Optical Society of Japan.