Abstract

In this Letter, we discuss a novel, to the best of our knowledge, approach for designing passive nanoantennas with maximum forward and almost-zero backward scattering. The proposed approach is based on the use of high-index dielectric spheres supporting dipolar magnetic resonances, which are coated by ultra-thin surface impedance coatings. It is shown that, by properly engineering the radius of the coat and its surface reactance, it is possible to introduce an additional electric dipolar resonance and to make this overlap with the magnetic one sustained by the high-index dielectric sphere. A realistic design that is based on graphene and works in the low-THz range is also proposed and verified with full-wave simulations. Compared to earlier techniques based on the combination of multipoles or on the use of ellipsoidal particles, the proposed one is quite robust toward realistic ohmic losses and preserves the isotropic behavior of the nanoantenna.

© 2022 Optica Publishing Group

Dual-band unidirectional forward scattering with all-dielectric hollow nanodisk in the visible

Xiao Ming Zhang, Qiang Zhang, Shang Jie Zeng, Zhen Zhen Liu, and Jun-Jun Xiao
Opt. Lett. 43(6) 1275-1278 (2018)

Forward Brillouin scattering acoustic impedance sensor using thin polyimide-coated fiber

Desmond M. Chow and Luc Thévenaz
Opt. Lett. 43(21) 5467-5470 (2018)

A generalized Kerker condition for highly directive nanoantennas

R. Alaee, R. Filter, D. Lehr, F. Lederer, and C. Rockstuhl
Opt. Lett. 40(11) 2645-2648 (2015)

Resonant forward scattering of light by high-refractive-index dielectric nanoparticles with toroidal dipole contribution

Pavel D. Terekhov, Kseniia V. Baryshnikova, Alexander S. Shalin, Alina Karabchevsky, and Andrey B. Evlyukhin
Opt. Lett. 42(4) 835-838 (2017)

On the surface impedance modeling of metasurfaces composed of graphene-coated spherical nanoparticles

Shiva Hayati Raad, Zahra Atlasbaf, Alessio Monti, Alessandro Toscano, and Filiberto Bilotti
J. Opt. Soc. Am. B 39(3) 917-923 (2022)