Geodesic elements to control terahertz surface plasmons

Geodesic elements (prisms, lenses, and beam splitters) are suggested to control (focus, deflect, and split) beams of terahertz (THz) surface plasmons (SPs). A geodesic deflector made in the form of conical trench crossing a SP beam can be effectively used not only for deflection of the beam but also for separation of surface and bulk electromagnetic waves. Formulae for calculating the angle of SP beam deflection with a geodesic prism as well as the angle of divergence of SP beams at the output of the geodesic splitter have been obtained. Schemes of THz SP absorption sensor and interferometer based on geodesic elements are discussed as well.