Design and Analysis of a Graphene Based Slotted Bowtie Optical Plasmonic Nanoantenna

A graphene-based modified bowtie plasmonic nanoantenna resonating in the optical frequency spectrum with the periodic directors created by the slots on top of the radiating structure has been proposed in this paper. In the field of nanophotonics, a few optical nanoantennas have been reported to construct multipath wireless nanolinks. At the telecommunication wavelength of 1550 nm (193.5 THz), the maximum directivity of 9.67 dBi has been reached due to the maximum absorption power of graphene sheet by selecting the chemical potential of 0.5 eV. Since graphene supports surface plasmon polariton waves and acts either as an absorptive or transparent medium for distinct chemical potentials, the proposed graphene-based slotted bowtie optical nanoantenna has been optimized to obtain a dynamically controlled triple-directional radiation beam. With this distinctive nature, a multipath intra or inter on-chip wireless nanolink for secure optical data transfer can be realized by integrating a set of our proposed optical plasmonic nanoantennas.

Driving plasmonic nanoantennas at perfect impedance matching using generalized coherent perfect absorption

Coherent perfect absorption (CPA) describes the absence of all outgoing modes from a lossy resonator, driven by lossless incoming modes. Here, we show that for nanoresonators that also exhibit radiative losses, e.g., plasmonic nanoantennas, a generalized version of CPA (gCPA) can be applied. In gCPA outgoing modes are suppressed only for a subset of (guided plasmonic) modes while other (radiative) modes are treated as additional loss channels - a situation typically referred to as perfect impedance matching. Here we make use of gCPA to show how to achieve perfect impedance matching between a single nanowire plasmonic waveguide and a plasmonic nanoantenna. Antennas with both radiant and subradiant characteristics are considered. We further demonstrate potential applications in background-free sensing.