Study on photon migration path of ultrashort light pulse in turbid media by Monte Carlo method

The photon density and the photon weight density are obtained by a Monte Carlo method. Based on these two concepts the Gaussian peak value photon paths and the weight mean photon paths of ultrashort light pulse in turbid media are defined and studied. The width of the Gaussian peak value photon path is also given. The influence of the exit angle and time on the photon path and its width are discussed. The relative probability of the photon path is given by the sum of the photon weight densities along the photon path, which could be used to calculate the normalized diffusive intensity approximately. The diffusive reflective intensities will arrive at the maximum at some instant at the place where the photon path reaches on the entrance surface at the same instant. The absorption coefficient has small effect on the photon path and its width in the case of the photon weight density.