用蒙特卡罗法模拟积分球的光传输时间特性

运用蒙特卡罗法原理,用Matlab软件编程,通过随机抽样,追迹了100 000个光子,对一半径为100mm,漫反射率为0.85的积分球的光传输时间特性进行了仿真分析.结果显示:积分球对入射光脉冲具有展宽作用,当入射光为脉宽无限窄的理想脉冲时,积分球的出射光能量波形符合指数曲线规律.对模拟数据进行指数拟合,得到了各拟合系数及相关系数.在此基础上对方波函数的输出响应进行模拟,得到了分段指数曲线,进一步验证了积分球对脉冲的展宽作用.两种情况下拟合的时间常数基本一致,拟合的相关系数大于0.97.

Monte-Carlo simulation on the time performance of light transmission of the integrating sphere

Based on Monte-Carlo fundamentals,by Matlab program, the time performance of light transmission by an integrating sphere with radius of 100 mm and diffuse reflectance of 0.85 was simulated.100 000 photons were randomly sampled and traced.The results show that the input pulse can be broadened by the integrating sphere.And the output light power pattern is of exponential form when the input pulse width is infinitely small.By data fitting,all the fitting coefficients and the correlation coefficients were obtained.Furthermore,the transient response for the square wave input of the integrating sphere was simulated and the piecewise exponential curve was derived.The pulse broadening effect of the sphere is verified again.The time constant is found to be approximately the same as the former.In both cases,the correlation coefficient is generally greater than 0.97.