{
  "abstract": "We propose a bias-assisted active photon-number conversion scheme for axion-induced polarization rotation in a four-port optical ring cavity with parametric readout. A calibrated real polarization rotation applied \\emph{before} the final optical parametric oscillator (OPO) converts the otherwise quadratic response of the summed output photon number into a linear signal. We derive the resulting photon moments and the extracted-field covariance, retaining the four-port optical transfer, finite axion coherence and linewidth. Our principal phenomenological result is a prospective low-mass sensitivity window at $m_a=10^{-18}$--$10^{-16}\\,\\mathrm{eV}$, extending below the published exclusion bounds included in our comparison, notably the NuSTAR M82 limits. This is a conditional noise-equivalent projection, using the adopted $A/σ_A=1$ stochastic-power criterion and a parameterized technical-noise budget, not a confidence-level exclusion forecast. As a separate readout result, OPO-based total counting reduces the noise-equivalent coupling by approximately $5\\%$ relative to matched selective attenuation in a favorable higher-frequency band; $5\\%$ internal loss together with a $0.10$-rad pump-phase offset leaves a $3.5\\%$ advantage in the stated example. A coherent input with only the final OPO retains this high-frequency benefit, whereas optimized coherent polarimetry remains more sensitive in the baseline. Our results identify both the operating principle of active number conversion and the stability requirements for a future implementation.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2611.03340",
  "author_total": 3,
  "authors": [
    {
      "name": "Antonio Capolupo"
    },
    {
      "name": "Gabriele Pisacane"
    },
    {
      "name": "Raoul Serao"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/dmry8pnan3fhj.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2611.03340",
  "fulltext_url": null,
  "id": "dmry8pnan3fhj",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2611.03340",
  "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",
      "hep-ex"
    ],
    [
      "arxiv",
      "hep-ph"
    ],
    [
      "arxiv",
      "physics.optics"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2611.03340",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-02",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/dmry8pnan3fhj.ris",
  "sources": [
    {
      "first_seen": "2026-11-03T12:21:04Z",
      "native_id": "2611.03340",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2611.03340"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-ex",
      "subfield": "high-energy"
    },
    {
      "field": "physics",
      "origin": "arxiv:physics.optics",
      "subfield": "optics-photonics"
    }
  ],
  "title": "Axion polarimetry with parametric readout: photon-number conversion and sensitivity limits",
  "title_text": "Axion polarimetry with parametric readout: photon-number conversion and sensitivity limits",
  "type": "preprint",
  "updated_at": "2026-11-05T15:20:21Z",
  "url": "https://research.draconitic.com/paper/dmry8pnan3fhj",
  "venue": "arXiv",
  "versions": []
}