The Diffusion Approximation in Three Dimensions

  • Scott A. Prahl
Part of the Lasers, Photonics, and Electro-Optics book series (LPEO)

Abstract

The diffusion approximation of the radiative transport equation is used extensively because closed-form analytical solutions can be obtained. The previous chapter gave closed-form solutions to the one-dimensional diffusion equation. In this chapter, the classic searchlight problem of a finite beam of light normally incident on a slab or semi-infinite medium will be solved in the timeindependent diffusion approximation. The solution follows naturally once the Green’s function for the problem is known, and so the Green’s function subject to homogeneous Robin boundary conditions will be given for semi-infinite and slab geometries. The diffuse radiant fluence rates are then found for impulse, flat (constant), and Gaussian shaped finite beam irradiances.

Keywords

Catheter Attenuation Expense Convolution Refraction 

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Copyright information

© Springer Science+Business Media New York 1995

Authors and Affiliations

  • Scott A. Prahl
    • 1
  1. 1.Oregon Medical Laser CenterPortlandUSA

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