{
  "abstract": "Photoionization of the excited nitrogen-vacancy center (NV-) in diamond leaves the neutral defect in a metastable quartet state of unknown energy. Using two-photon optically detected magnetic resonance with a tunable femtosecond laser, we resolve its onset in the spin contrast at 1.23 +/- 0.02 eV and, with the ground-state threshold from the same setup, place the quartet 0.54 +/- 0.04 eV above the neutral ground state. The threshold sets the optimum excitation for spin readout at 1060-1075 nm, in the near-infrared tissue window, with 26-37% higher shot-noise-limited sensitivity than at 1030-1040 nm.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2611.03343",
  "author_total": 7,
  "authors": [
    {
      "name": "Nikoletta Jegenyes"
    },
    {
      "name": "Pál Maák"
    },
    {
      "name": "Vladimir Verkhovlyuk"
    },
    {
      "name": "László Himics"
    },
    {
      "name": "Tamás Váczi"
    },
    {
      "name": "Miklós Veres"
    },
    {
      "name": "Ádám Gali"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/1gpmmhgdkwb1p.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2611.03343",
  "fulltext_url": null,
  "id": "1gpmmhgdkwb1p",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2611.03343",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "quant-ph"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2611.03343",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-02",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/1gpmmhgdkwb1p.ris",
  "sources": [
    {
      "first_seen": "2026-11-03T12:21:04Z",
      "native_id": "2611.03343",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2611.03343"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Quartet state of the neutral nitrogen-vacancy center in diamond and optimized spin readout under near-infrared two-photon excitation",
  "title_text": "Quartet state of the neutral nitrogen-vacancy center in diamond and optimized spin readout under near-infrared two-photon excitation",
  "type": "preprint",
  "updated_at": "2026-11-05T15:20:21Z",
  "url": "https://research.draconitic.com/paper/1gpmmhgdkwb1p",
  "venue": "arXiv",
  "versions": []
}