Electrical detection of plasmonic waves using an ultra-compact structure via a nanocavity.

A novel structure is proposed to electrically detect the plasmonic waves from a subwavelength plasmonic waveguide. By locating two L-shaped metallic nanorods in close proximity of each other at the end of the plasmonic waveguide, a metal-semiconductor-metal plasmonic detector is constructed. The L-shaped nanorods also form a dipole nanoantenna and a nanocavity to focus the photonic power into the active volume of the detector. The dimensions and locations of the L-shaped nanorods are studied to maximize the transmission efficiency of the photonic power from the plasmonic waveguide to the detector. Impedance matching with a sub is investigated to further improve the power transmission. Possible leads of the detector are discussed and their effects are investigated. Proposed detector has an ultra-compact and easy-to-fabricate planar structure, and a potentially THz speed, high responsivity as well as low power dissipation.