Ts. Aurora et al., DILATOMETRIC AND THERMOOPTIC PROPERTIES OF ALKALINE-EARTH AND CADMIUMFLUORIDES BETWEEN 300 AND 1300-K, Journal of applied physics, 76(4), 1994, pp. 2122-2128
Temperature variation of the coefficients of linear thermal expansion
and optical length was measured with an interferometer using 632.8 nm
wavelength light from a He-Ne laser over the temperature range of 300-
1300 K. The experiment was carried out under a high vacuum to minimize
sample oxidation. For the optical length variation, the laser beam wa
s allowed to pass through the crystals while, for the thermal expansio
n work, the laser beam was reflected from a coating of platinum deposi
ted on the faces of crystals. Temperature variation of the coefficient
of refractive index was calculated from the measurements of the coeff
icients of linear expansion and optical length variation. The results
were used to calculate temperature variation of the optically importan
t quantities such as molecular polarizability, energy band gap, refrac
tive index variation with density, and the strain-polarizability param
eter with the help of the Lorentz-Lorenz relation. The optical quantit
ies exhibit a small variation over the temperature range of 300- appro
ximately 800 K. The results were compared to the values in available l
iterature.