Intra-bandgap Bound-State Magnonics in a Photonic Crystal Waveguide
Abstract
Cavity and waveguide magnonics have recently emerged as frontiers for investigating light-matter interactions. In these systems, coupling magnons into meticulously engineered photonic lattices with rich band structures provides a promising platform for tailoring magnon-photon interactions. However, how these hybrid interactions behave in the bandgaps of photonic lattices---specifically, the formation of magnon-photon bound states (MPBSs)---remains largely unaddressed. Crucially, these bound states arise through a mechanism that is fundamentally distinct from bound states in the continuum (BICs). Here, we experimentally demonstrate intra-bandgap bound-state magnonics by coupling yttrium iron garnet (YIG) spheres to a microwave photonic crystal waveguide. At room temperature, we observe MPBSs featuring highly tunable spatial localization, power-dependent interaction modulation under microwave pumping, and long-range magnon-magnon interactions mediated by mode overlap. These unique features bridge fundamental insights into intra-bandgap light-matter interactions with practical applications, offering an avenue for scaling up coherent networks and investigating many-body physics through engineered interactions.
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BibTeX
@misc{run2026intrabandgap,
title = {{Intra-bandgap Bound-State Magnonics in a Photonic Crystal Waveguide}},
author = {Chong-Xin Run and Xue-Feng Pan and Bang-Yao Wu and Kai-Min Hsieh and Wei-Min Zhou and Anton Frisk Kockum and Peng-Bo Li and Io-Chun Hoi},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.25744},
eprint = {2609.25744},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.25744},
}
RIS
TY - UNPB
TI - Intra-bandgap Bound-State Magnonics in a Photonic Crystal Waveguide
AU - Chong-Xin Run
AU - Xue-Feng Pan
AU - Bang-Yao Wu
AU - Kai-Min Hsieh
AU - Wei-Min Zhou
AU - Anton Frisk Kockum
AU - Peng-Bo Li
AU - Io-Chun Hoi
PY - 2026
DA - 2026/09/22
PB - arXiv
DO - 10.48550/arxiv.2609.25744
UR - https://arxiv.org/abs/2609.25744
AB - Cavity and waveguide magnonics have recently emerged as frontiers for investigating light-matter interactions. In these systems, coupling magnons into meticulously engineered photonic lattices with rich band structures provides a promising platform for tailoring magnon-photon interactions. However, how these hybrid interactions behave in the bandgaps of photonic lattices---specifically, the formation of magnon-photon bound states (MPBSs)---remains largely unaddressed. Crucially, these bound states arise through a mechanism that is fundamentally distinct from bound states in the continuum (BICs). Here, we experimentally demonstrate intra-bandgap bound-state magnonics by coupling yttrium iron garnet (YIG) spheres to a microwave photonic crystal waveguide. At room temperature, we observe MPBSs featuring highly tunable spatial localization, power-dependent interaction modulation under microwave pumping, and long-range magnon-magnon interactions mediated by mode overlap. These unique features bridge fundamental insights into intra-bandgap light-matter interactions with practical applications, offering an avenue for scaling up coherent networks and investigating many-body physics through engineered interactions.
ER -