One way optical waveguides for matched non-reciprocal nanoantennas with dynamic beam scanning functionality

Abstract

Matching circuits for waveguide-nanoantenna connections are difficult to implement. However, if the waveguide permits only one-way propagation, the matching issue disappears since back-reflections cannot take place; the feed signal is converted to radiation at high efficiency. Hence, a terminated one-way waveguide may serve as an assembly consisting of a waveguide, a matching mechanism, and an antenna. Since one-way structures are inherently non-reciprocal, this antenna possesses different transmit and receive patterns. We test and demonstrate this concept on a recently suggested new class of one-way plasmonic waveguides and present an additional significant dynamic beam scanning functionality.

Planar one-way guiding in periodic particle arrays with asymmetric unit cell and general group-symmetry considerations

“…Since one-way guiding inherently supresses propagation in the "wrong" direction, applications that require minimization of backreflections may benefit. These applications can be, for example, new ways to feed electromagnetic components as antennas and resonators in a perfectly matched fashion [2,3].…”

“…They find applications as isolators and circulators, as a mean to reduce disorder effects in waveguides [1], or even as a mean to match waveguide to a load [2] or to a leaky wave nano-antenna [3].…”

Breaking temporal symmetries for emission and absorption

“…For instance, a nanoscale plasmonic nonreciprocal antenna was proposed in ref. 17, but its requirements on magnetic biasing make it largely impractical. Alternatively, reciprocity can be also broken with nonlinearities (18, 19); however, this leads to undesirable signal distortion and a powerdependent response.…”

Plasmon-Polariton Properties in Metallic Nanosphere Chains

“…The calculus of plasmon self-mode frequencies, their attenuation rates and group velocities are presented for longitudinal and transverse polarizations of collective excitations and for the wide range of chain parameters. A problem of the logarithmic singular contribution caused by the far-field component of the dipole interaction has also been resolved, for the self-energy of plasmon-polaritons with transverse polarization and the similar one caused by the medium-field component for the group velocity of both polarizations, with some link to a recent discussion of numerical simulations of long-range kinetics of plasmon-polaritons in metallic nano-chains [32–36]. …”