Optically driven plasmons in graphene/hBN van der Waals heterostructures: simulating s-SNOM measurements

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• Autor: Neven Golenić
• Autor: Stefano de Gironcoli
• Autor: Vito Despoja
• Autorova ustanova: Sveučilište u Zagrebu; Prirodoslovno-matematički fakultet; (Fizički odsjek)
• Znanstveno / umjetničko područje, polje i grana: PRIRODNE ZNANOSTI; Fizika

Sažetak (engleski)

Converting transverse photons into longitudinal two-dimensional plasmon-–polaritons (2D-PP) and vice versa presents a significant challenge within the fields of photonics and plasmonics. Therefore, understanding the mechanism which increases the photon – 2D-PP conversion efficiency could significantly contribute to those efforts. In this study, we theoretically examine how efficiently incident radiation, when scattered by a silver spherical nanoparticle (Ag-NP), can be transformed into 2D-PP within van der Waals (vdW) heterostructures composed of hexagonal boron nitride and graphene (hBN/Gr composites). We show that the Dirac plasmon (DP) excitation efficiency depends on the Ag-NP radius as R 3, and decreases exponentially with Ag-NP height h, so that for a certain Ag-NP geometry up to 25 % of the incident electrical field is channeled into the DP. We demonstrate that the linear plasmons (LPs) excitation efficiency can be manipulated by changing the graphene–graphene distance Δ (or hBN thickness) or by changing the number of graphene layers N. By increasing Δ and/or N the LPs move towards smaller wave vectors Q and become accessible by the Ag-NP dipole field, so that for N ≥ 5 the excitation of more than one LP is possible. These results are supported by recent scattering-type scanning near-field optical microscopy (s-SNOM) measurements. Furthermore, we show that Ag-NPs with specific parameters preferentially hybridizes with DPs of a particular wavelength λ D , facilitating selective excitation of DPs. The obtained tuning possibilities could have a significant impact on applied plasmonics, photonics or optoelectronics.

• Ključne riječi (engleski): s-SNOM; graphene; hBN; photons; optical excitations; Dirac plasmon polariton
• Jezik: engleski
• Vrsta publikacije: Znanstveni rad - Izvorni znanstveni rad
• Status objave: Objavljen
• Vrsta recenzije: Recenziran - međunarodna recenzija
• Verzija publikacije: Objavljena verzija rada (izdavačev PDF)
• Naslov časopisa: Nanophotonics
• Brojčani podaci: vol. 13, br. 15, str. 2765-2780
• e-ISSN: 2192-8614
• DOI: https://doi.org/10.1515/nanoph-2023-0841
• URN:NBN: urn:nbn:hr:217:244372
• Datum objave publikacije: 2024-07-04
• Projekt: Šifra: KK.01.1.1.01.0004; Naziv (hrvatski): Provedba vrhunskih istraživanja u sklopu Znanstvenog centra izvrsnosti za kvantne i kompleksne sustave te reprezentacije Liejevih algebri; Naziv (engleski): Implementation of top research within the Scientific Center of Excellence for Quantum and Complex Systems, and Representations of Lie Algebras; Kratica: QuantiXLie; Voditelj: Hrvoje Buljan; Pravna nadležnost: eu; Financijer: Europska komisija; Linija financiranja: European Regional Development Fund
• Projekt: Šifra: IP-2020-02-5556; Naziv (hrvatski): Plazmoni i eksiton-polaritoni u kvazi-2D kristalima; Naziv (engleski): Plasmons and exciton-polaritons in quasi-2D crystals; Kratica: 2DPlasEx; Voditelj: Vito Despoja; Pravna nadležnost: Hrvatska; Financijer: Hrvatska zaklada za znanost; Linija financiranja: Research Projects
• URL dokumenta: https://www.degruyter.com/document/doi/10.1515/nanoph-2023-0841/html
• Vrsta resursa: Tekst
• Prava pristupa: Otvoreni pristup
• Javna napomena: © 2024 the author(s), published by De Gruyter. This work is licensed under the Creative Commons Attribution 4.0 International License. Received November 23, 2023; accepted March 22, 2024; published online April 15, 2024.
• Datum i vrijeme pohrane: 2024-08-01 12:08:20