Generation of broadband radially polarized terahertz radiation directly on a cylindrical metal wire

We demonstrate the ability to directly generate broadband THz surface plasmons via optical rectification on a cylindrical metal wire. This is accomplished by milling a single circumferential groove into the wire and overcoating it with a poled polymer that exhibits a bulk second order susceptibility. An attractive feature of this approach is the potential to generate THz pulses that are limited in duration only by the duration of the optical pump pulse. While a photoconductive detector is used in the present demonstration, we discuss further refinements to the system that should allow for significant enhancement of the nonlinear optical conversion efficiency and detection bandwidth.