Rapid, accurate and precise terahertz polarization modulation and ellipsometry with multi-pixel interdigitated photoconductive emitters

We demonstrate that multi-element interdigitated photoconductive emitters can rapidly and precisely modulate broadband terahertz radiation between linear (horizontal or vertical) and circular polarization states. The rapid electrical modulation between polarization states is beneficial for THz time-domain spectroscopic ellipsometry: it eliminates mechanical rotation and enhances the relevant figures of merit.