Thermal expansion of monoclinic KYbxY1–x(WO4)2 laser crystals

Potassium–yttrium tungstate single crystals KYbxY1–x(WO4)2 of high structural quality are grown by the modified Czochralski method. The crystals were grown using so-called dynamic growth regime, and optimal temperature gradients at the crystallization front were determined. The thermal expansion coefficients of KYbxY1–x(WO4)2 in the directions of the optical indicatrix axes Np, Nm and Ng are determined using the dilatometric technique. The dependence of thermal expansion coefficients on the temperature in the range of 330–573 K and ytterbium content x from 0 to 1.0 is discussed.