Lattice vibration and thermal diffusion of Yb doped KLu(WO4)2 single crystal.

Yb doped KLu(WO₄)₂ (Yb:KLuW) single crystal was grown by the method of top-seeded-solution growth slow-cooling method. Its lattice vibrational modes were calculated by using space group theory, and polarized Raman spectra were measured at room temperature with different scattering geometry projections. The powder transmission of Fourier-transform infrared spectra was also performed as a supplement for Raman spectra to study the lattice vibration of the laser crystal. The main Raman peaks and infrared transmission bands were attributed to the internal mode WO₆ octahedrons in the crystals. Two kinds of link ways of WO₆ octahedrons implying large distortion had led the Raman peaks to shift to different positions. Large distortions of the WO₆ octahedrons in the crystal had led to the splitting of some Raman peaks and even the activation of ν₆ mode, which is originally a silent mode by the selection rule. As a self-Raman crystal, the linewidth of the Raman peaks ν₁ and ν₂ reached 12.5 and 16.6 cm^-1, with relaxation times of 849.4 and 639.6 fs, respectively, indicating that it is a promising stimulated Raman scattering crystal. Thermal diffusion measurement of Yb:KLuW showed large anisotropy which could be explained by the different link ways of the WO₆ octahedrons. [ABSTRACT FROM AUTHOR]