Kim Arnold D, Moscoso Miguel
Department of Mathematics, Stanford University, Stanford, California 94305-2125, USA.
Opt Lett. 2004 Jan 1;29(1):74-6. doi: 10.1364/ol.29.000074.
For a beam impinging on a scattering medium the diffusion approximation to the radiative transport equation is not valid for analyzing the radiance near the source, especially if the medium scatters strongly with a sharp forward peak. To analyze the radiance, we use the Fokker-Planck approximation to the radiative transport equation. Numerical results show a backscattered ring appearing around the beam center. It also appears in Monte Carlo simulations of the radiative transport equation. This ring is manifested from successive near-forward scattering events, so it requires a directional description. Therefore the diffusion approximation cannot predict this ring.
对于入射到散射介质上的光束，辐射传输方程的扩散近似不适用于分析源附近的辐射率，特别是当介质具有强烈散射且向前散射峰尖锐时。为了分析辐射率，我们使用辐射传输方程的福克 - 普朗克近似。数值结果显示在光束中心周围出现一个后向散射环。它也出现在辐射传输方程的蒙特卡罗模拟中。这个环是由连续的近向前散射事件形成的，因此需要一个方向描述。所以扩散近似无法预测这个环。
