Patent ID: 6381018
Filing Date: 2002-04-30
Classification: G01N

Abstract:
An apparatus for measuring absorption of light by a material in small volume of highly scattering medium, which comprises in combination:(a) a source of light having a wavelength which is absorbed by said material; (b) a first optical fiber, having a first end for receiving the light from said source of light, and a second end for directing the light into the surface of the highly scattering medium, such that the light enters said highly scattering medium; (c) a second optical fiber, having a first end located approximately 1.7 mm from the second end of said first optical fiber on the surface of said highly scattering medium, for collecting and receiving a portion of the light scattered from the highly scattering medium in a direction opposite to the light entering the highly scattering medium, and a second end, whereby the dependence of the pathlength of the light traversing the highly scattering medium taken to reach the first end of said second fiber on the scattering parameters of the highly scattering medium is minimized; and (d) a light detector for detecting light exiting the second end of said second optical fiber, such that a measurement of the light absorbed by a portion of the material is obtained.