Guiding light with surface exciton-polaritons in atomically thin superlattices

Fuente: arXiv
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Autori principali: Elrafei, Sara A., Raziman, T. V., de Vega, Sandra, de Abajo, F. Javier García, Curto, Alberto G.
Natura: Preprint
Pubblicazione: 2024
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author Elrafei, Sara A.
Raziman, T. V.
de Vega, Sandra
de Abajo, F. Javier García
Curto, Alberto G.
author_facet Elrafei, Sara A.
Raziman, T. V.
de Vega, Sandra
de Abajo, F. Javier García
Curto, Alberto G.
contents 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; at energies close to an exciton, the real part of the permittivity can reach high positive values or even become negative. 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 consisting of monolayer WS$_2$ 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 improves the confinement of the TE mode from 1.2 to around 0.5 $μ$m, whereas 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 superlattices as a platform for visible nanophotonics with promising optical, electrical, and magnetic tunability
format Preprint
id arxiv_https___arxiv_org_abs_2402_10180
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Guiding light with surface exciton-polaritons in atomically thin superlattices
Elrafei, Sara A.
Raziman, T. V.
de Vega, Sandra
de Abajo, F. Javier García
Curto, Alberto G.
Optics
Mesoscale and Nanoscale Physics
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; at energies close to an exciton, the real part of the permittivity can reach high positive values or even become negative. 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 consisting of monolayer WS$_2$ 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 improves the confinement of the TE mode from 1.2 to around 0.5 $μ$m, whereas 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 superlattices as a platform for visible nanophotonics with promising optical, electrical, and magnetic tunability
title Guiding light with surface exciton-polaritons in atomically thin superlattices
topic Optics
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2402.10180