Measurement of optical rotation and phase retardance of optical samples with depolarization effects using linearly and circularly polarized probe lights

This paper presents an experimental technique for measuring the optical rotation, depolarization, and phase retardance of optical samples. In the proposed approach, the optical properties of the sample are derived using a Stokes-Mueller matrix formalism in conjunction with linearly and circularly polarized probe lights. For a compound sample comprising a half-wave plate positioned in front of glucose solutions with concentrations ranging from 0 to 1.2 g/dl, the average normalized error in the measured rotation angle is determined to be 3.11% when using a linearly polarized light. The average surviving linear and circular polarization fractions of the glucose solutions are determined to be 1.0252 and 0.9945. The average normalized error in the measured retardance of the half-wave plate is 3.45%. When measuring a compound sample comprising a half-wave plate positioned in front of the scattered glucose solutions with turbidities from 0% to 50% by the addition of milk, experimental results show that the induced rotation angle increased as the turbidity increased, whereas both surviving linear and circular polarization fractions decreased as the turbidity increased. The effect of the turbidity on rotation angle is more significant than that on both surviving linear and circular polarization fractions. The average normalized error in the measured retardance of the half-wave plate is 1.43%. Consequently, a simplified geometry of the polarimeter is proposed to independently estimate the rotation angle, surviving linear and circular polarization fractions, and retardance from the derived viable algorithm. (C) 2009 Elsevier Ltd. All rights reserved.