散射介质中光传输行为时间特性的蒙特卡洛模拟研究

Monte Carlo Simulations for Time Characteristics of Light Propagation in Scattering Medium

蒙特卡罗方法模拟了超短脉冲在皮肤的四层模型中的传输的时间特性 ,给出不同时间的表面漫射强度随径向距离和角度的变化 ,用傅里叶变换给出了表面漫射强度时间响应的频域结果 ;结果表明漫射强度随时间的变化会有数量级的不同 ,漫射强度的时间分辨为ps量级 ,这要求选择大动态范围 ps时间分辨率的探测设备 ,频域分析的结果表明在达到很高的频率下 ,幅度和相位才有变化 ,实际上硬件难以实现。

Monte Carlo simulations for time characteristics of ultrashort pulse light propagation in the skin four-striated scattering medium were presented. Variations of diffusive intensity with the radial distance and angle at different time were given. The frequency-domain results of time response of surface diffusive intensity were obtained by using Fourier transformation. The results show that the diffusive intensity changes with time to the extent of magnitude and its time-resolution is in the order of ps, so the detector with large dynamic range and ps time-resolution is needed. The results from the frequency-domain analysis show that the amplitude and phase have significant changes at very high frequency, but the realization of the detection is not feasible.