{
  "abstract": "Optical nanoscopies including near-field optical microscopy and spectroscopy circumvent the diffraction limit of conventional optics thanks to the nanoscale light focus emerging at the apex of a sharp irradiated probe. However, while strong optical coupling between the apex and its dielectric environment affords both enhanced nanoscopic measurement sensitivity and potentially ultra-strong fields within a nano-gap cavity, the conditions for this coupling remain poorly quantified by prevailing analytic models. Here we present a robust formalism of probe-cavity eigenmodes that fully describes how mutual near-field interactions between probe and environment produce a composite response to external fields qualitatively distinct from that of its distinct components. This \"EigenProbe\" model identifies the fundamental excitations of realistic optical nanoscopies as nano-gap polaritons, which provide an elegant basis to accurately predict near-field microscopy and spectroscopy experiments especially when probe-sample interactions are non-perturbative. Through comparison to carefully controlled nanoscopies of polar phonons and molecular vibrations alike, we show how nano-gap polaritons are both realized and utilized for reliable and rapid \"inversion\" of local optical constants. This advance demands both a careful understanding of the probe response through quantitative calibration, and our efficient semi-analytic description of cavity eigenmode scattering at the probe apex. Our EigenProbe formalism sets the stage for maturing diverse and proliferating optical nanoscopies into precision metrologies of nano-scale optical environments, and guides future use of nano-gap cavities to manipulate local excitations of quantum materials and to achieve strong coupling over photonic emitters.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2607.23950",
  "author_total": 9,
  "authors": [
    {
      "name": "Benjamin Allen"
    },
    {
      "name": "Brayden Lukaskawcez"
    },
    {
      "name": "Alyssa Bragg"
    },
    {
      "name": "Nitzan Hirshberg"
    },
    {
      "name": "Michael Fogler"
    },
    {
      "name": "Dimitri N. Basov"
    },
    {
      "name": "Stephanie N. Gilbert Corder"
    },
    {
      "name": "Hans A. Bechtel"
    },
    {
      "name": "Alexander S. McLeod"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/0155tztyqpan3.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2607.23950",
  "fulltext_url": null,
  "id": "0155tztyqpan3",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2607.23950",
  "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",
      "cond-mat.mes-hall"
    ],
    [
      "arxiv",
      "physics.optics"
    ],
    [
      "openalex",
      "2204|Near-Field Optical Microscopy"
    ]
  ],
  "openalex": "W7171506286",
  "pdf_url": "https://arxiv.org/pdf/2607.23950",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-06",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/0155tztyqpan3.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:19:48Z",
      "native_id": "2607.23950",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2607.23950"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mes-hall",
      "subfield": "condensed-matter"
    },
    {
      "field": "physics",
      "origin": "arxiv:physics.optics",
      "subfield": "optics-photonics"
    }
  ],
  "title": "Quantitative infrared nanoscopy: Probe-cavity eigenmodes and nano-gap polaritons for strongly coupled nanoscale optics",
  "title_text": "Quantitative infrared nanoscopy: Probe-cavity eigenmodes and nano-gap polaritons for strongly coupled nanoscale optics",
  "type": "preprint",
  "updated_at": "2026-10-30T12:19:48Z",
  "url": "https://research.draconitic.com/paper/0155tztyqpan3",
  "venue": "arXiv",
  "versions": []
}