{
  "annotation_id": "38ff086d-2a74-44c8-bdb7-4355197d2ca3",
  "date_created": "2026-03-02T18:01:41.780000Z",
  "date_modified": "2026-03-02T18:01:41.780000Z",
  "file_hash": "ee077544e359bba0eeaae94c11fbd46fd7b514ebbd412c5b1440037cae1c65f2",
  "private": false,
  "record": {
    "abstract": "The problem of the quantum-limited or intrinsic linewidth of a good-cavity\nlaser is revisited. Starting from the Scully-Lamb master equation, we present a\nfully analytical treatment to determine the correlation function and the\nspectrum of the cavity field at steady state. For this purpose, we develop an\nanalytical approximation method that implicitly incorporates the microscopic\nfluctuations of both the phase and intensity of the field, and, in addition,\ntakes full account of the saturation of the nonlinear gain. Our main result is\na simple formula for the quantum-limited linewidth that is valid from near to\nfar above threshold and also includes the presence of thermal photons. Close to\nthe threshold, the linewidth is twice as large as predicted by the standard\nphase-diffusion treatment neglecting intensity fluctuations, and even 50% above\nthreshold the increase is still considerable. In general, quantum fluctuations\nof the intensity are present and continue to influence the linewidth as long as\nthe photon-number distribution is not strictly Poissonian. This inherent\nrelationship is displayed by a formula relating the linewidth and the Mandel\nQ-parameter. More than 100% above treshold the linewidth is found to be smaller\nthan predicted by the standard treatment, since the simple phase-diffusion\nmodel increasingly overestimates the rate of phase fluctuations by neglecting\ngain saturation. In the limit of a very large mean photon number the expected\nperfectly coherent classical field is obtained.",
    "arxiv_id": "quant-ph/0011003",
    "authors": [
      "Ulrike Herzog",
      "J\u00e1nos A. Bergou"
    ],
    "categories": [
      "quant-ph"
    ],
    "doi": "10.1103/PhysRevA.62.063814",
    "title": "Quantum-limited linewidth of a good-cavity laser: An analytical theory   from near to far above threshold",
    "url": "https://arxiv.org/abs/quant-ph/0011003"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "71246772-c6bd-4374-9efd-6cbd287f875f",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}