A Cherenkov Source for Freely-Propagating Terahertz Beams’

Using a unique cylindrical optical arrangement, we have coupled out a Cherenkcv electromagnetic shock wave from the confining dielectric substrate and have used this shock wave as a source to produce freely-propagating terahertz beams. The shock wave is initially generated by a surface-dipole distribution propagating faster than the phase velocity in the underlying dielectric substrate. © 1989 IEEE