Realization and characterization of terahertz surface plasmon light capsules

Surface plasmon waves with unique intensity profiles are important for developing integrated photonic circuits. By organically combining a Bessel-like terahertz (THz) beam in free space and a metallic semicircular slit, we generate a THz surface plasmon light capsule (TSPLC) in simulation and experiment. The TSPLC has a two-dimensional optical barrier on the surface of a metal foil. Furthermore, we propose and theoretically validate the potential use of the TSPLC in refractive index sensing. This work has major implications for manipulating and applying surface plasmon waves.