Patent ID: 6687012
Filing Date: 2004-02-03
Classification: G01N

Abstract:
An apparatus for measuring the circular birefringence of a sample comprising:(a) a reference polarizer positioned to receive a reference beam having a right circularly polarized (RCP) wave characterized by a first frequency and a left circularly polarized (LCP) wave characterized by a second frequency, the reference polarizer producing a reference heterodyne wave, the reference heterodyne wave characterized by a reference phase, the reference phase representing the difference between the RCP wave and the LCP wave of the reference beam; (b) a reference detector positioned to receive the reference heterodyne wave and generate a reference signal; (c) a measurement polarizer positioned to receive a measurement beam exiting the sample, the measurement beam having a RCP wave characterized by the first frequency and a LCP wave characterized by the second frequency, the measurement polarizer producing a measurement heterodyne wave, the measurement heterodyne wave characterized by a measurement phase, the measurement phase representing the difference between the RCP wave and the LCP wave of the measurement beam; (d) a sample detector positioned to receive the measurement heterodyne wave and generate a measurement signal; (e) a gain/phase meter connected to the reference detector and sample detector and generating an output signal characterized by a phase difference equal to the difference between the measurement phase and the reference phase; and (f) a control program capable of execution on a processor, the control program calculating the circular birefringence of the sample based, in part, on the output signal of the gain/phase meter.