Patent ID: 7233395
Filing Date: 2007-06-19
Classification: G01J,G01N

Abstract:
1. A system for determining a light transmission intensity curve, comprising: means for transmitting light along a light transmission axis; means for positioning a polarizer along the light transmission axis, the polarizer having a polarization transmission direction substantially perpendicular to the light transmission axis; means for positioning an analyzer along the light transmission axis, the analyzer having a polarization transmission direction substantially perpendicular to the light transmission axis; means for interposing a first waveplate between the polarizer and the analyzer, the first waveplate being located along the light transmission axis, the first waveplate having a slow axis, the slow axis of the first waveplate being substantially perpendicular to the light transmission axis; means for interposing a second waveplate between the polarizer and the analyzer, the second waveplate being located along the light transmission axis, the second waveplate having a slow axis, the slow axis of the second waveplate being substantially perpendicular to the light transmission axis; means for selecting i angles, each of the i angles being defined with reference to the polarization transmission direction of the polarizer, i being an integer greater than 1; means for recursively rotating the second waveplate such that the slow axis of the second waveplate is substantially oriented to each of the i angles at each of the recursive rotations, the second waveplate being recursively rotated about the light transmission axis; means for obtaining a light intensity measurement for the transmitted light at each of the i angles; means for determining a light transmission intensity curve from the obtained light intensity measurements; means for inverting the equation: by solving the equation: where: means for calculating: and means for calculating: