Guiding light with surface exciton–polaritons in atomically thin superlattices
File(s)
Published version
Author(s)
Elrafei, Sara A
Raziman, TV
de Vega, Sandra
García de Abajo, F Javier
Curto, Alberto G
Type
Journal Article
Abstract
Two-dimensional materials give access to the ultimate physical limits of photonics with appealing properties for ultracompact optical components such as waveguides and modulators. Specifically, in monolayer semiconductors, a strong excitonic resonance leads to a sharp oscillation in permittivity from positive to even negative values. This extreme optical response enables surface exciton–polaritons to guide visible light bound to an atomically thin layer. However, such ultrathin waveguides support a transverse electric (TE) mode with low confinement and a transverse magnetic (TM) mode with short propagation. Here, we propose that realistic semiconductor–insulator–semiconductor superlattices comprising monolayer WS2 and hexagonal boron nitride (hBN) can improve the properties of both TE and TM modes. Compared to a single monolayer, a heterostructure with a 1-nm hBN spacer separating two monolayers enhances the confinement of the TE mode from 1.2 to around 0.5 μm, while the out-of-plane extension of the TM mode increases from 25 to 50 nm. We propose two simple additivity rules for mode confinement valid in the ultrathin film approximation for heterostructures with increasing spacer thickness. Stacking additional WS2 monolayers into superlattices further enhances the waveguiding properties. Our results underscore the potential of monolayer-based superlattices as a platform for visible-range nanophotonics with promising optical, electrical, and magnetic tunability.
Date Issued
2024-07-01
Date Acceptance
2024-04-25
Citation
Nanophotonics, 2024, 13 (17), pp.3101-3111
ISSN
2192-8606
Publisher
De Gruyter
Start Page
3101
End Page
3111
Journal / Book Title
Nanophotonics
Volume
13
Issue
17
Copyright Statement
Open Access. © 2024 the author(s), published by De Gruyter. This work is licensed under the Creative Commons Attribution 4.0 International License.
License URL
Identifier
10.1515/nanoph-2024-0075
Subjects
exciton-polaritons
2D semiconductors
WS 2
van der Waals heterostructures
Publication Status
Published
Date Publish Online
2024-05-20