Anisotropic thermal properties of Yb:YCOB crystal influenced by doping concentrations

The effect of the doping concentration on the anisotropic thermal properties of Yb:YCOB crystals was systematically evaluated for the first time to our knowledge. The thermal expansion, thermal diffusion, specific heat and thermal conductivity of Yb:YCOB crystals with different doping concentrations were measured. The thermal expansion and conductivity along the principal axes were calculated, and the rotation angles between the thermal frame and the reference coordinate were determined. The relationship between the doping concentration and the anisotropic thermal properties was discussed with the results that the doping concentration was an anomaly found to have a slight impact on anisotropic thermal properties. It was concluded that the YCOB crystal can be doped with a high concentration of Yb3+ ions to improve the conversion efficiency in the laser process without deteriorative thermal problems. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement