Ultrastrong coupling of topologically protected edge and bulk magnetoplasmons without a dedicated cavity
Abstract
In the ultrastrong light-matter coupling regime, the ability to confine the electric field to subwavelength scales and define an electromagnetic mode is essential. This task is typically achieved through dedicated cavities, such as THz metal resonators. Here, we instead introduce ultrastrong coupling directly between distinct magnetoplasmon excitations, leveraging solely the spatial symmetry of a confined electronic medium in the presence of a magnetic field. By patterning an AlGaN/GaN single quantum well hosting a two-dimensional electron gas into micrometer-scale patches, we tailor the mutual interactions between topologically protected edge and bulk magnetoplasmons, achieving coupling strengths of up to 0.1. The progressive breaking of rotational symmetry determines the coupling rules and leads to the emergence of energy gaps and unique chiral-mode hybridization. Our results highlight a path towards exploiting the symmetry class and topology of the magnetoplasmon wavefunction as a new parameter space for ultrastrong light-matter interaction without a dedicated cavity.
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BibTeX
@misc{velli2026ultrastrong,
title = {{Ultrastrong coupling of topologically protected edge and bulk magnetoplasmons without a dedicated cavity}},
author = {F. Velli and P. Sai and M. Dub and J. Dzian and F. Le Mardele and M. Mittendorff and M. Orlita and W. Knap and C. Lange},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.27575},
eprint = {2609.27575},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.27575},
}
RIS
TY - UNPB
TI - Ultrastrong coupling of topologically protected edge and bulk magnetoplasmons without a dedicated cavity
AU - F. Velli
AU - P. Sai
AU - M. Dub
AU - J. Dzian
AU - F. Le Mardele
AU - M. Mittendorff
AU - M. Orlita
AU - W. Knap
AU - C. Lange
PY - 2026
DA - 2026/09/23
PB - arXiv
DO - 10.48550/arxiv.2609.27575
UR - https://arxiv.org/abs/2609.27575
AB - In the ultrastrong light-matter coupling regime, the ability to confine the electric field to subwavelength scales and define an electromagnetic mode is essential. This task is typically achieved through dedicated cavities, such as THz metal resonators. Here, we instead introduce ultrastrong coupling directly between distinct magnetoplasmon excitations, leveraging solely the spatial symmetry of a confined electronic medium in the presence of a magnetic field. By patterning an AlGaN/GaN single quantum well hosting a two-dimensional electron gas into micrometer-scale patches, we tailor the mutual interactions between topologically protected edge and bulk magnetoplasmons, achieving coupling strengths of up to 0.1. The progressive breaking of rotational symmetry determines the coupling rules and leads to the emergence of energy gaps and unique chiral-mode hybridization. Our results highlight a path towards exploiting the symmetry class and topology of the magnetoplasmon wavefunction as a new parameter space for ultrastrong light-matter interaction without a dedicated cavity.
ER -