Experimental Demonstration of Tunable Directional Scattering of Visible Light from All-Dielectric Asymmetric Dimers

Abstract

Due to the presence of strong magnetic resonances, high refractive index dielectric nanoantennnas have shown the ability to expand the methods available for controlling electromagnetic waves in the subwavelength region. In this work, we experimentally demonstrate that an asymmetric dielectric dimer made of silicon can lead to highly directional scattering depending on the excitation wavelength, due to the interference of the excited magnetic resonances. A back focal plane imaging system combined with a prism coupling technique enables us to explore the scattering profile parallel to the substrate. The directivity of scattering along the substrate is high enough to produce selective guiding of light along the substrate. These results showing tunable control of directional scattering will encourage the realization of novel optical applications, such as optical nanocircuitry.

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

“…2 and 3 can be directly applied. Figures 4(a)-4(c) show the efficient routing for light of different colors to different directions based on an asymmetric silicon dimer, which is induced mainly by the interferences of the two MDs excited within each particle [92]. Similar studies has also been conducted for trimers and oligomers with more consisting particles, and Figs.…”

“…Then the scattering properties of the whole cluster can be obtained through a linear combination of the contributions from all the multipoles excited within all the particles of the cluster, taken into consideration also the phase lags among the particles. One of the simplest versions of multiple scattering theory is the coupled dipole theory that involves not only ED modes but also MD modes [89], which has been widely applied for various particle clusters, including dimers [90][91][92][93], trimers [90,[94][95][96], quadrumers [90,97], and other types of oligomers [98]. Based on the coupled-dipole theory, it is also possible to calculate directly the eigenmodes of the whole cluster [91,97,99], making it possible to treat the whole cluster effectively as an individual scattering particle, and then the basic principles discussed above in Secs.…”

“…Besides angular scattering controls in (a-d), the total scattering can be significantly suppressed for the quadrumer made of high-index dielectric spheres shown in (g), or fully eliminated for that consisting of high-index dielectric cylinders shown in (h), where simultaneous free-space field enhancement has also been obtained. Adapted from[90,92,97,101].…”

Fano-resonances in High Index Dielectric Nanowires for Directional Scattering

“…In early 2013, two research groups around Novotny and Luk'yanchuk published almost at the same time their results on exclusive forward or backward scattering from dielectric nanoparticles [60,76]. Since then, similar results have been achieved for different geometries of dielectric nanoparticles, like nanodiscs [77], nanospheroids [78] or nanosphere dimers for switchable directional scattering [79][80][81].…”

Engineering Nanoparticles with Pure High-Order Multipole Scattering

“…The latter is highly beneficial due to low, almost negligible absorption losses, compatibility with well-established semiconductor fabrication processes, and abundance of different optical modes (and corresponding resonances) even for simple * zenin@mci.sdu.dk † a.b.evlyukhin@daad-alumni.de symmetric shapes of dielectric nanoparticles [3][4][5]. The above advantages led to a broad variety of applications utilizing dielectric nanoparticles, including light manipulation with metasurfaces [6][7][8][9][10][11][12], color printing [13,14], lasing [15,16], biosensing [17][18][19], strong coupling [20][21][22][23], and applications within quantum optics and topological photonics [24][25][26].…”