Highly tunable propagating surface plasmons on supported ITO nanowire metamaterial

Few things are known about metal-less nanowires, however it is commonly known that surface plasmons—the quanta of the collective oscillations of free electrons at a metal surface—can be easily tuned for metal nanoparticles and metal surfaces. Here, we discover that surface plasmons on nanowires composed of alternative plasmonic materials, like ITO, have a highly tunable nature, which can be adjusted by adjusting the carrier concentration and, consequently, the properties of ITO. Calculated dispersion relations, propagation lengths of plasmon modes in the system are presented. This allows us to characterize and categorize the modes into two groups: Ferrel-Berreman modes and surface plasmon polaritons. Such high sensitivity is necessary to directly regulate the optical signal dispersion for various routing and demultiplexing operations in plasmonic circuits and could pave the way for the development of on-chip ultrasensitive biosensing.