Experimental method to characterize a liquid-crystal variable retarder and its application in a Stokes polarimeter.

We present an experimental method to characterize a liquid-crystal variable retarder (LCVR). In addition, experimental results using LCVR’s to measure the four Stokes parameters of a light beam simultaneously are presented. We use known waveplates (half-wave and quarter-wave) as devices to provide controlled polarization states to the Stokes polarimeter, and we use the measured Stokes parameters as functions of the orientation of the axes of the waveplates as an indication of the quality of the polarimeter. Also, we present results of simulations for comparison.