Tunable plasmonic Yagi-Uda nanoantenna

Abstract

We suggest and theoretically study a novel tunable plasmonic Yagi-Uda nanoantenna driven by means of a feed element consisting of two closely spaced metal nanobars separated by a gap filled with a semiconductor. Through extensive numerical simulations we demonstrate that a variation of the free-carrier density in the semiconductor strongly modifies the antenna's response in both near-field and far-field regions, which opens up ways for active all-optical spectral tuning of the nanoantenna.