Collective photonic response of high refractive index dielectric metasurfaces

Sushanth Reddy Amanaganti (Avtor), Miha Ravnik (Avtor), Jayasri Dontabhaktuni (Avtor)

Povzetek

Sub-wavelength periodic nanostructures give rise to interesting optical phenomena like efective refractive index, perfect absorption, cloaking, etc. However, such structures are usually metallic which results in high dissipative losses and limitations for use; therefore, dielectric nanostructures are increasingly considered as a strong alternative to plasmonic (metallic) materials. In this work, we show light-matter interaction in a high refractive index dielectric metasurface consisting of an array of cubic dielectric nano-structures made of very high refractive index material, Te in air, using computer modelling. We observe a distinct band-like structure in both transmission and refection spectra resulting from the near-feld coupling of the feld modes from neighboring dielectric structures followed by a sharp peak in the transmission at higher frequencies. From the spatial distribution of the electric and magnetic felds and a detailed multipole analysis in both spherical harmonics and Cartesian components, the dominant resonant modes are identifed to be electric and magnetic dipoles. Specifcally at lower frequency (60 THz) a novel anapole-like state characterized by strong-suppression in refection and absorption is observed, reported very recently as ‘lattice-invisibility’ state. Diferently, at higher frequency (62 THz), strong absorption and near-zero far feld scattering are observed, which combined with the feld profles and the multipole analysis of the near-felds indicate the excitation of an anapole. Notably the observed novel modes occur in the simple geometry of dielectric cubes and are a result of collective response of the metasurfaces. Periodicity of the cubic metasurface is shown as the signifcant material tuning parameter, allowing for the near-feld and far-feld coupling efects of anapole metasurface. More generally, our work is a contribution towards developing far-fetching applications based on metamaterials such as integrated devices and waveguides consisting of non-radiating modes.

Ključne besede

optika;fotonika;metamateriali;optics;photonics;metamaterials;

Podatki

Jezik:	Angleški jezik
Leto izida:	2020
Tipologija:	1.01 - Izvirni znanstveni članek
Organizacija:	UL FMF - Fakulteta za matematiko in fiziko
UDK:	535
COBISS:	29884163
ISSN:	2045-2322
Št. ogledov:	45
Št. prenosov:	15
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Slovenski jezik
Sekundarne ključne besede:	optika;fotonika;metamateriali;
Vrsta dela (COBISS):	Članek v reviji
Strani:	8 str.
Letnik:	ǂVol. ǂ10
Zvezek:	ǂart. no. ǂ15599
Čas izdaje:	Sep. 2020
DOI:	10.1038/s41598-020-72675-3
ID:	18264587