{
  "annotation_id": "e7ed91ce-6896-4876-ae45-51a46a54dc10",
  "date_created": "2026-03-02T18:01:00.056000Z",
  "date_modified": "2026-03-02T18:01:00.056000Z",
  "file_hash": "7490e1f2eafb15b8e25af656dbd1676e22e3ee26e661f0b1bdcfe4df912f5db1",
  "private": false,
  "record": {
    "abstract": "We measure and stabilize the relative angle of (anti-)parallel laser beams to\n5 nanoradian per root Hertz resolution by comparing the phases of radio\nfrequency beat notes on a quadrant photodetector. The absolute accuracy is 5.1\nmicroradian and 2.1 microradian for antiparallel and parallel beams,\nrespectively, which is more than 6 and 16 times below the Rayleigh criterion.",
    "arxiv_id": "physics/0507039",
    "authors": [
      "Holger Mueller",
      "Sheng-wey Chiow",
      "Quan Long",
      "Christoph Vo",
      "Steven Chu"
    ],
    "categories": [
      "physics.optics",
      "physics.atom-ph"
    ],
    "doi": "10.1364/OL.30.003323",
    "journal_ref": "Optics Letters 30, 3323 (2005)",
    "title": "Active sub-Rayleigh alignment of parallel or antiparallel laser beams",
    "url": "https://arxiv.org/abs/physics/0507039"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "4bf0eda0-e661-4d42-8845-4b514a54e8fa",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}