# this file is part of refractiveindex.info database
# refractiveindex.info database is in the public domain
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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>α</sub>; 22 °C.
CONDITIONS:
    temerature: 295
    direction: alpha
DATA:
  - type: formula 4
    wavelength_range: 0.40 5.3
    coefficients: 4.4222 0.09972 0 0.05496 1 0 0 0 1 -0.01976 2