Patent ID: 6480277
Filing Date: 2002-11-12
Classification: G01J

Abstract:
A dual circular polarization modulator spectrometer comprising, in combination:a light source; a wavelength selection device; a first polarizer; a first polarization modulator vibrated to modulate incoming light between left and right circular polarized light at a selected frequency; a sample chamber; a second polarization modulator vibrated to modulate incoming light between left and right circular polarized light at a selected frequency that is not the same frequency as the selected frequency for the first polarization modulator whereby strength of the first a polarization modulator and strength of the second polarization modulator can be manipulated to eliminate unwanted background signal; second polarizer; a light detector; a first lock-in amplifier whereby a signal corresponding to the selected frequency of the first polarization modulator is isolated; a second lock-in amplifier whereby a signal corresponding to the selected frequency of the second polarization modulator is isolated; an electronic manipulator to combine the signals from the first and the second lock-in amplifiers whereby the signals can be combined by mathematical operations.