Structure and Vibration Spectrum of Laser Crystal Yb:KGd(WO_4)_2

The selection of the flux and the design of the proper processes are the key factor for the growth of Yb:KGd(WO4)2 laser crystal. Yb:KGd(WO4)2 crystal was grown by the Top Seeded Solvent Growth (TSSG) method using K2W2O7 as a suitable flux. On the base of TG-DTA, the crystal has two obvious absorption peaks at 1086℃ and 1021℃, its melting point is 1086℃, phase transition temperature from tetragonal to monoclinic is 1021℃. The Yb:KGd(WO4)2 crystal consists of WO6 octahedra which consists of WOOW double oxygen bridges and WOW single bridges. IR and Raman spectra show the atom group WO42- flex vibration at 436 cm-1 and atom group WO42- bend vibration at 740-925cm-1, WOOW double oxygen bridge vibration at 903, 765, 684, 438, 498 and 297cm-1, WOW single bridges vibration at 808, 526 and 232cm-1. Analyzing on the X-ray diffraction spectrum of Yb:KGd(WO4)2 crystal powder sample, we can conclude that the β-Yb:KGd(WO4)2 crystal is of a monoclinic system, and C2/c space group.