Generation of radially polarized terahertz pulses via velocity-mismatched optical rectification.

We demonstrate the generation of radially polarized terahertz pulses via optical rectification in a Cherenkov geometry exploiting velocity mismatch, contrary to the traditional approach for generating linearly polarized terahertz beams. A compact system is implemented using 001-cut ZnTe pumped by an ultrafast Yb-doped fiber amplifier.