Compact Ultrabroadband Plasmonic Antenna: Potential Applications in Logic Binary Encoding

A compact ultrabroadband coupling and binary encoding structure based on an array of aperiodic nanoslits cascaded by two different pairs of grooves in a metallic-dielectric-air waveguide is proposed and theoretically analyzed. The nanoslits array function as a broadband antenna to couple the incident lights into surface plasmon polaritons (SPPs) over an ultrawide wavelength range (spectral full-width-half-maximum >430 nm). The two ports composed of different grooves exhibit different transmission for the coupled multiwavelength SPPs. After traveling through different ports, the incident lights dropping in different wavelength ranges are differentiated and endowed with different logic state encodings. The operation principle is clarified and a coupled-mode model is developed for facilitating design.