In order to measure the retardation of the liquid crystal variable retarder(LCVR) attached with the compensator

a new method is presented in this paper

which is based on Stokes vector and Mueller matrix. This method is simple

precise and no mechanism rotating. A 2 kHz square wave of adjustable amplitude 0-10V is used to control LCVR and the retardation is measured at six wavelengths. The experiment results show that LCVR has the advantages of low voltage controlling

simple operation

wide adjustment range and no need rotating. The error of measurement is less than 0.6%. The fitting function is established based on the characteristics of the retarders. The method of the least-square curve fitting is used to obtain retardation of all wavelengths and all voltages in the working condition of the retarders. The standard error of curve fitting is less than 0.02λ. The measurement method

the experiment results and the fitting function are useful for the polarization device research.