کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1495301 | 992932 | 2011 | 7 صفحه PDF | دانلود رایگان |
Thermooptic coefficients dn/dT for monoclinic potassium (rare-earth) double tungstates KRe(WO4)2 (where Re = Gd, Y, Lu, Yb) were determined at eight wavelengths in the range of 0.3–1.1 μm by a laser beam deviation method. In the long-wavelength range all the dn/dT values were found to be negative and near constant, while dn/dT(λ) dependence is especially pronounced in the short-wavelength range where thermooptic coefficients change sign to positive. Linear thermal expansion coefficients were measured in KRe(WO4)2 along the optical indicatrix axes by a dilatometric technique. Volumetric thermal expansion effect was found to dominate over the bandgap change influence on temperature dependence of the refractive index. Thermooptic dispersion formulas were derived for KRe(WO4)2 as series in 1/λ2. The influence of Yb and Nd doping on the dn/dT values was investigated, resulting in prediction of thermooptic coefficients evolution in the isostructural KYxYb(1−x)(WO4)2 and KYbxLu(1−x)(WO4)2 series.
► Monoclinic potassium (rare-earth) double tungstates KRe(WO4)2 (Re = Gd, Y, Lu, Yb).
► Thermooptic coefficients study at 0.3–1.1 μm for light polarizations E || Np, Nm, Ng.
► Linear thermal expansion measurements in the directions of Np, Nm, Ng axes.
► Negative dn/dT values are determined by large volumetric thermal expansion.
Journal: Optical Materials - Volume 33, Issue 11, September 2011, Pages 1688–1694