Polarization modulation time-domain terahertz polarimetry
  We present high precision measurements of polarization rotations in the frequency range from 0.1 to 2.5 THz using a polarization modulation technique. A motorized stage rotates a polarizer at ~80 Hz, and the resulting modulation of the polarization is measured by a lock-in technique. We achieve an accuracy of 0.05{\deg} (900 {\mu}rad) and a precision of 0.02{\deg} (350 {\mu}rad) for small rotation angles. A detailed mathematical description of the technique is presented, showing its ability to fully characterize elliptical polarizations from 0.1 to 2.5 THz. 
C. M. Morris, R. Vald\'es Aguilar, A. V. Stier, N. P. Armitage
physics.optics cond-mat.mtrl-sci cond-mat.str-el physics.ins-det