{
  "annotation_id": "f647dd4b-5219-4f13-88a0-b6b09b8432a7",
  "date_created": "2026-03-02T18:00:39.429000Z",
  "date_modified": "2026-03-02T18:00:39.429000Z",
  "file_hash": "d22ea4e4c29df9e880284e7bd2e4a3630f575755929723b64f2fd59568d4b234",
  "private": false,
  "record": {
    "abstract": "The dispersive properties of non-degenerate optical parametric amplification\nin quasi-phase-matched (QPM) nonlinear quadratic crystals with an arbitrary\ngrating profile are theoretically investigated in the no-pump-depletion limit.\nThe spectral group delay curve of the amplifier is shown to be univocally\ndetermined by its spectral power gain curve through a Hilbert transform. Such a\nconstraint has important implications on the propagation of spectrally-narrow\noptical pulses through the amplifier. In particular, it is shown that anomalous\ntransit times, corresponding to superluminal or even negative group velocities,\nare possible near local minima of the spectral gain curve. A possible\nexperimental observation of such effects using a QPM Lithium-Niobate crystal is\nsuggested.",
    "arxiv_id": "physics/0204059",
    "authors": [
      "S. Longhi",
      "M. Marano",
      "P. Laporta"
    ],
    "categories": [
      "physics.optics",
      "physics.class-ph"
    ],
    "doi": "10.1103/PhysRevA.66.033803",
    "title": "Dispersive properties of quasi-phase-matched optical parametric   amplifiers",
    "url": "https://arxiv.org/abs/physics/0204059"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "8ded166a-0cc1-49ba-a15b-fa3aa17aafeb",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}