{
  "abstract": "Polarization topology in momentum space is a fundamental characteristic of photonic bound states in the continuum (BICs), where the winding of far-field polarization defines a quantized topological charge. Although magneto-optical (MO) BICs combine polarization topology with magnetically tunable chirality, experimental characterization remains challenging because time-reversal symmetry (TRS) breaking complicates eigenpolarization extraction. Here, we experimentally resolve the momentum-space polarization topology of an MO BIC by reconstructing its two-dimensional far-field eigenpolarization texture. We extract the resonant output polarization using singular value decomposition of the polarization-resolved angle-resolved reflection matrix without invoking reciprocity. The reconstructed polarization azimuth winds counterclockwise by 2$π$ around the $Γ$-point singularity, yielding a topological charge of q = +1. Moreover, the polarization handedness can be reversed solely by varying the magnetic-bias strength, while the field direction and the measured topological charge remain unchanged. A non-Hermitian coupled-mode model traces this reversal to hybridization between the BIC mode and a leaky mode. This work establishes experimental access to momentum-space polarization topology in nonreciprocal photonics, opening a route to explore topological singularities and their evolution under active TRS breaking.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.31498",
  "author_total": 10,
  "authors": [
    {
      "name": "Yaqi Li"
    },
    {
      "name": "Mingyu Tong"
    },
    {
      "name": "Fujia Chen"
    },
    {
      "name": "Li Zhang"
    },
    {
      "name": "Rui Zhao"
    },
    {
      "name": "Yuze Hu"
    },
    {
      "name": "Bei Wu"
    },
    {
      "name": "Haiyao Luo"
    },
    {
      "name": "Hongsheng Chen"
    },
    {
      "name": "Yihao Yang"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/e2dfmd79gn54s.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.31498",
  "fulltext_url": null,
  "id": "e2dfmd79gn54s",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.31498",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "physics.optics"
    ],
    [
      "openalex",
      "3107|Topological Materials and Phenomena"
    ]
  ],
  "openalex": "W7223370639",
  "pdf_url": "https://arxiv.org/pdf/2610.31498",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-22",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/e2dfmd79gn54s.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:34:34Z",
      "native_id": "2610.31498",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.31498"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:physics.optics",
      "subfield": "optics-photonics"
    }
  ],
  "title": "Observation of Polarization Topology in Magneto-Optical BICs",
  "title_text": "Observation of Polarization Topology in Magneto-Optical BICs",
  "type": "preprint",
  "updated_at": "2026-10-30T12:34:34Z",
  "url": "https://research.draconitic.com/paper/e2dfmd79gn54s",
  "venue": "arXiv",
  "versions": []
}