{
  "meta": {
    "api_version": "v1",
    "attribution": "lithium-niobate.com data compiled by Wentao Jiang; cite the original sources listed per value.",
    "data_version": "0.1.0",
    "documentation": "https://lithium-niobate.com/api/openapi.json",
    "license": {
      "id": "CC-BY-4.0",
      "name": "Creative Commons Attribution 4.0 International",
      "url": "https://creativecommons.org/licenses/by/4.0/"
    },
    "model": "zelmon1997-cln-e"
  },
  "model": {
    "axis": "e",
    "check_values": [
      {
        "T_C": 21,
        "lambda_nm": 632.8,
        "n": 2.2022,
        "source": "computed from these coefficients",
        "tolerance": 6e-05
      },
      {
        "T_C": 21,
        "lambda_nm": 1064,
        "n": 2.1555,
        "source": "computed",
        "tolerance": 6e-05
      },
      {
        "T_C": 21,
        "lambda_nm": 1550,
        "n": 2.1376,
        "source": "computed",
        "tolerance": 6e-05
      },
      {
        "T_C": 24.5,
        "lambda_nm": 632.8,
        "n": 2.2028,
        "source": "Nelson & Mikulyak 1974 via weis1985 Table 2; Zelmon is 6e-4 lower",
        "tolerance": 0.0008
      },
      {
        "T_C": 24.5,
        "lambda_nm": 1060,
        "n": 2.1561,
        "source": "Nelson & Mikulyak 1974 via weis1985 Table 2",
        "tolerance": 0.0008
      }
    ],
    "coefficient_units": {
      "B1": "1",
      "B2": "1",
      "B3": "1",
      "C1": "um2",
      "C2": "um2",
      "C3": "um2"
    },
    "coefficients": {
      "B1": 2.9804,
      "B2": 0.5981,
      "B3": 8.9543,
      "C1": 0.02047,
      "C2": 0.0666,
      "C3": 416.08
    },
    "default": true,
    "errata": [],
    "formula": {
      "expression": "n^2 - 1 = B1 L^2/(L^2 - C1) + B2 L^2/(L^2 - C2) + B3 L^2/(L^2 - C3), L in um",
      "form": "sellmeier-3term",
      "latex": "n^2 - 1 = \\sum_{i=1}^{3} \\frac{B_i \\lambda^2}{\\lambda^2 - C_i}",
      "rii_formula": 2
    },
    "id": "zelmon1997-cln-e",
    "lambda_unit": "um",
    "name": "Zelmon 1997, congruent LiNbO3, extraordinary",
    "provenance": {
      "locator": "Table 2 (via refractiveindex.info LiNbO3 Zelmon-e)",
      "source_id": "zelmon1997",
      "status": "P-db",
      "transcribed": "2026-10-25",
      "via": "rii"
    },
    "public": true,
    "reference_T_C": 21,
    "temperature_dependent": false,
    "valid_T_C": null,
    "valid_lambda_um": [
      0.4,
      5.0
    ],
    "variant": "cln"
  },
  "python": "def n(L_um):\n    B = (2.9804, 0.5981, 8.9543); C = (0.02047, 0.0666, 416.08)\n    L2 = L_um * L_um\n    return (1 + sum(b * L2 / (L2 - cc) for b, cc in zip(B, C))) ** 0.5\n"
}