Abstract: Time-resolved spectroscopy is expected to be developed for imaging of buried absorbers inside strongly scattering media. It is required to know the temporal behaviors of the reflectance and/or transmittance produced by the propagation of light impulse incident on scattering and absorbing media. The Monte Carlo method (MC) is the most frequently used numerical method, but its computation time is considerably long to obtain the results with a satisfactory accuracy. A faster numerical method is required for analysis of temporal profiles of reflectance and transmittance through random media with complicated configurations. One of the methods to solve the photon diffusion equation numerically is finite element method (FEM). This paper reports the FEM results of temporal profiles of transmittance of light impulse through scattering slabs and cylinders. Time courses of transmittances through homogeneously scattering and absorbing slabs are obtained by FEM and compared with those by MC. The results of cylinders with homogeneous scattering and inhomogeneous absorption coefficients are also presented. Temporal variations of the cross-sectional profiles of the fluence rate generated by impulse incident on a surface are shown by contour plotting, and the effect of the location and size of the localized absorbing volume on the transmittances are discussed. !22
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