Rotating waveplate Stokes polarimeter using anisotropic transmittance in waveplate.

One of well-known polarization measurement techniques is a rotating waveplate Stokes polarimeter. This technique modulates the polarization state by rotating a quarter waveplate, and the polarization state can be identified from the second and the fourth harmonics of the modulated detector signal. This study presents a new signal model and a new calibration method for the rotating waveplate Stokes polarimeter using an anisotropic-transmittance quarter waveplate. It was found that anisotropic transmittance enables identification of the light intensity and the degree of polarization without measuring the DC (direct current) component of the intensity of the modulated polarized light. In addition, anisotropic transmittance enables the calibration of the rotating waveplate Stokes polarimeter by using only linearly polarized light. The experiment was carried out to demonstrate the measurement capability of the polarimeter using the anisotropic-transmittance waveplate and the 95% confidence interval of the error was 0%-1.9%.