Collective photonic response of high refractive index dielectric metasurfaces

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

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.

• Language: English
• Keywords: optics, photonics, metamaterials, optical materials, optical structures
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FMF - Faculty of Mathematics and Physics
• Publication status: Published
• Publication version: Version of Record
• Year: 2020
• Number of pages: 8 str.
• Numbering: Vol. 10, art. 15599
• PID: 20.500.12556/RUL-144810
• UDC: 535
• ISSN on article: 2045-2322
• DOI: 10.1038/s41598-020-72675-3
• COBISS.SI-ID: 29884163
• Publication date in RUL: 14.03.2023

Record is a part of a journal

• Title: Scientific reports
• Shortened title: Sci. rep.
• Publisher: Nature Publishing Group
• ISSN: 2045-2322
• COBISS.SI-ID: 18727432

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: optika, fotonika, metamateriali