# this file is part of refractiveindex.info database
# refractiveindex.info database is in the public domain
# copyright and related rights waived via CC0 1.0

REFERENCES: "N. Umemura, K. Yoshida, and K. Kato. Phase-matching properties of KNbO<sub>3</sub> in the mid-infrared, <a href=\"    https://doi.org/10.1364/AO.38.000991\"><i>Appl Opt.</i> <b>38</b>, 991-994 (1999)</a>"
COMMENTS: "n<sub>γ</sub>; 22 °C."
DATA:
  - type: formula 4
    wavelength_range: 0.40 5.3
    coefficients: 4.9856 0.15266 0 0.06331 1 0 0 0 1 -0.02831 2 2.0754e-6 4 -1.2131e-6 6
