Magnetoplasmonic Slotted Yagi-Uda Nanoantennas for Nanoscale Wireless Optical Signals

In this letter, a magnetoplasmonic slotted Yagi-Uda nanoantenna is theoretically investigated. In particular, we numerically demonstrate that the active control of the radiated field directivity can be achieved, by exploiting magneto-optical (MO) effects. The proposed device consists of a set of slots arranged following a Yagi-Uda-like model, providing 7.87 times higher electric field enhancement than its complementary ribs counterpart. The slots are considered made in a magnetoplasmonic thin slab, constituted of Co6Ag94 ferromagnetic material immersed in SiO2. The structure is optimized to operate at
$\lambda = 860$
nm to take advantage of the highest magneto-optical activity of Co6Ag94. The radiated field maximum steering angle is found as
$\phi _{\mathrm{ s}}=\pm 10^{\circ }$
, which can be flipped by reversing the magnetization sense along the magnetized axis. The results of this work are promising for future nanoscale wireless optical communications, which are expected to overcome the ohmic losses of conventional metallic wires/waveguides.