Scattering Invisibility With Free‐Space Field Enhancement of All‐Dielectric Nanoparticles

Abstract

Simultaneous scattering invisibility and free‐space field enhancement have been achieved based on multipolar interferences among all‐dielectric nanoparticles. The scattering properties of all‐dielectric nanowire quadrumers are investigated and two sorts of scattering invisibilities have been identified: the trivial invisibility where the individual nanowires are not effectively excited; and the nontrivial invisibility with strong multipolar excitations within each nanowire, which results in free‐space field enhancement outside the particles. It is revealed that such nontrivial invisibility originates from not only the simultaneous excitations of both electric and magnetic resonances, but also their significant magnetoelectric cross‐interactions. We further show that the invisibility obtained is both polarization and direction selective, which can probably play a significant role in various applications including non‐invasive detection, sensing, and non‐disturbing medical diagnosis with high sensitivity and precision.

Beam Steering with Dielectric Metalattices

“…We name the structure under consideration as "metalattices", which is broader term and includes both regimes of metagratings and metasurfaces. Based on the multiple scattering theory, [42][43][44] the optical properties of the metalattice shown in Fig. 1(a) can be obtained through direct analytical calculations.…”

Anapole Mode Sustaining Silicon Metamaterials in Visible Spectral Range

“…All these properties lead to extensive research of all‐dielectric and, particularly, silicon metamaterials and their many applications. 2D metamaterials or metasurfaces stand out due to the simplicity of fabrication and exhibits desirable optical properties . Nevertheless, we should mention the ref.…”

“…2D metamaterials or metasurfaces stand out due to the simplicity of fabrication and exhibits desirable optical properties. [11,22,[31][32][33][34][35][36][37][38][39] Nevertheless, we should mention the ref. [40], in which the possibility of an anapole excitation in 3D plasmonic toroidal metamaterials of the optical range has been shown.…”

Selective Third-Harmonic Generation by Structured Light in Mie-Resonant Nanoparticles

“…A further step is made with a quadrumer consisting of high-index dielectric cylinders [see Fig. 4(h)], and it is shown that the scattering can be totally eliminated, making the quadrumer effectively invisible [101]. Together with invisibility, the fields are also enhanced in the accessible free space between the cylinders, which has been made possible by efficient excitations of not only ED and MD modes, but also higher-order multipoles within each cylinder [101].…”

“…Together with invisibility, the fields are also enhanced in the accessible free space between the cylinders, which has been made possible by efficient excitations of not only ED and MD modes, but also higher-order multipoles within each cylinder [101]. It is worth noticing that when higher-order multipoles within either particle are effectively excited (as is the case discussed in [101]), the coupled dipole theory can not be simply applied, and more general multiple scattering theory should be employed. Moreover, for such a system it is not convenient or direct to conduct an eigenmode analysis for the whole cluster (as has been done in [97]), because here you have to consider interactions not only between ED and MD modes, but also between higher-order multipoles.…”