title: Rotating-polarizer polarimeter for accurate retardance measurement.
abstract: We demonstrate an automated polarimeter based on a rotating polarizer for the measurement of linear retardance independent of laser power and detector gain. The retardance is found when a curve is fitted to a unique normalization of the intensity response of the polarimeter over a range of input polarizer orientations. The performance of this polarimeter is optimal for measurements of quarter-wave retardance and minimal for half-wave retardance. Uncertainties are demonstrated by measurements on six stable double Fresnel rhombs of nominal quarter-wave retardance, yielding expanded uncertainties between 0.031 degrees and 0.067 degrees . The accuracy has also been verified by blind comparisons with interferometric and modified null retardance measurement techniques.
authors.forename: P A
authors.initials: PA
authors.lastname: Williams
authors.forename: A H
authors.initials: AH
authors.lastname: Rose
authors.forename: C M
authors.initials: CM
authors.lastname: Wang