{
  "annotation_id": "9428cdbd-e009-411c-b2fb-243e32a7b758",
  "date_created": "2026-03-02T18:01:03.283000Z",
  "date_modified": "2026-03-02T18:01:03.283000Z",
  "file_hash": "19886b40f9ced164f6b386f043d9e140fc5ca1a563b0d05ad8ef9915a895a9a8",
  "private": false,
  "record": {
    "abstract": "We present a method that formally calculates \\emph{exact} frequency shifts of\nan electromagnetic field for arbitrary changes in the refractive index. The\npossible refractive index changes include both anisotropic changes and boundary\nshifts. Degenerate eigenmode frequencies pose no problems in the presented\nmethod. The approach relies on operator algebra to derive an equation for the\nfrequency shifts, which eventually turn out in a simple and physically sound\nform. Numerically the equations are well-behaved, easy implementable, and can\nbe solved very fast. Like in perturbation theory a reference system is first\nconsidered, which then subsequently is used to solve another related, but\ndifferent system. For our method precision is only limited by the reference\nsystem basis functions and the error induced in frequency is of second order\nfor first-order basis set error. As an example we apply our method to the\nproblem of variations in the air-hole diameter in a photonic crystal fiber.",
    "arxiv_id": "physics/0511197",
    "authors": [
      "Lars Rindorf",
      "Niels Asger Mortensen"
    ],
    "categories": [
      "physics.optics"
    ],
    "doi": "10.1016/j.optcom.2005.11.053",
    "journal_ref": "Opt. Commun. 261, 181 (2006).",
    "title": "Non-perturbative approach to high-index-contrast variations in   electromagnetic systems",
    "url": "https://arxiv.org/abs/physics/0511197"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "055431f8-1efc-4c0a-949c-b94ccc18b2e6",
    "id": "arXiv Dataset IDs",
    "type": "Model",
    "variant": "snapshot-2026-03-01",
    "version": "0.1.0"
  },
  "user_id": 1000002
}