Tailoring Flatband Dispersion in Bilayer Moiré Photonic Crystals

Fuente: arXiv
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Main Authors: Saadi, Chirine, Cueff, Sébastien, Ferrier, Lydie, Benamrouche, Aziz, Gayrard, Maxime, Drouard, Emmanuel, Letartre, Xavier, Nguyen, Hai Son, Callard, Ségolène
Format: Preprint
Published: 2025
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author Saadi, Chirine
Cueff, Sébastien
Ferrier, Lydie
Benamrouche, Aziz
Gayrard, Maxime
Drouard, Emmanuel
Letartre, Xavier
Nguyen, Hai Son
Callard, Ségolène
author_facet Saadi, Chirine
Cueff, Sébastien
Ferrier, Lydie
Benamrouche, Aziz
Gayrard, Maxime
Drouard, Emmanuel
Letartre, Xavier
Nguyen, Hai Son
Callard, Ségolène
contents In this study, we experimentally investigate the photonic dispersion in one-dimensional moiré structures formed by stacking two photonic crystal slabs with slightly different periods, separated by a carefully controlled subwavelength optical spacer. Angle-resolved reflectivity measurements reveal moiré bands arising from the interplay between intra- and inter-layer coupling mechanisms of guided modes mediated by the moiré superlattice corrugation. By precisely adjusting the refractive index contrast through the filling factor of the photonic crystals, we continuously tune intralayer coupling while keeping interlayer coupling constant. Consequently, we experimentally demonstrate the evolution of moiré minibands into flatbands characterized by minimal dispersion bandwidth. All experimental results show good agreement with numerical simulations. Our findings not only confirm theoretical predictions but also provide a practical approach for realizing photonic flatbands in silicon-based moiré superlattices operating in the telecom wavelength range. This work paves the way toward harnessing flatband physics in advanced optoelectronic applications such as lasers and optical sensors.
format Preprint
id arxiv_https___arxiv_org_abs_2504_18670
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Tailoring Flatband Dispersion in Bilayer Moiré Photonic Crystals
Saadi, Chirine
Cueff, Sébastien
Ferrier, Lydie
Benamrouche, Aziz
Gayrard, Maxime
Drouard, Emmanuel
Letartre, Xavier
Nguyen, Hai Son
Callard, Ségolène
Optics
In this study, we experimentally investigate the photonic dispersion in one-dimensional moiré structures formed by stacking two photonic crystal slabs with slightly different periods, separated by a carefully controlled subwavelength optical spacer. Angle-resolved reflectivity measurements reveal moiré bands arising from the interplay between intra- and inter-layer coupling mechanisms of guided modes mediated by the moiré superlattice corrugation. By precisely adjusting the refractive index contrast through the filling factor of the photonic crystals, we continuously tune intralayer coupling while keeping interlayer coupling constant. Consequently, we experimentally demonstrate the evolution of moiré minibands into flatbands characterized by minimal dispersion bandwidth. All experimental results show good agreement with numerical simulations. Our findings not only confirm theoretical predictions but also provide a practical approach for realizing photonic flatbands in silicon-based moiré superlattices operating in the telecom wavelength range. This work paves the way toward harnessing flatband physics in advanced optoelectronic applications such as lasers and optical sensors.
title Tailoring Flatband Dispersion in Bilayer Moiré Photonic Crystals
topic Optics
url https://arxiv.org/abs/2504.18670