User:Garrenangacian/sandbox

Introduction
The collimated transmission method is a direct way of measuring the optical properties of materials. It is especially useful for sensing the optical properties of tissues to guide developments of both diagnostic and therapeutic techniques. These optical properties are described by the absorption coefficient μa, scattering coefficient μs, and anisotropy factor g.

In the collimated transmission method, a laser beam is directed perpendicularly to the material and the detection of reemitted light gives information about the total interactive effect of the optical properties of the material. [1] The use of multiple wavelengths can produce a spectra with more detailed information about the composition of the tissue or material (spectroscopy).

While this method is simple and requires only minimal instrumentation, it produces error related to multiple scattering events and specular reflection. [2] Some useful equations governing the properties include: μa = absorption coefficient = Na𝜎a; μs = scattering coefficient = Ns𝜎s; g = scattering anisotropy = ; μt  = extinction coefficient = μa + μs Where Na is the number of absorbers in a medium, 𝜎a is the absorption cross section, Ns is the number of scatterers in a medium, 𝜎s is the scattering cross section, and 𝛳 is the scattering angle.