Planar THz quasioptics

Abstract
Two-dimensional (2D) quasioptical elements are demonstrated as guiding structures in the THz frequency regime. A planar polyethylene lens is incorporated in a parallel metal plate structure and is shown to focus guided THz radiation to a spot comparable to that expected for a three-dimensional (3D) optical element in free space. A 2D double-slit aperture is also demonstrated to diffract the incoming THz beam as expected for 3D. The spatial resolution of the measurement techniques employed is illustrated by the sharpness of the measured diffraction pattern.