Growth, spectroscopy and laser operation of Yb:KGd(PO(3))(4) single crystals

Macrodefect-free single crystals of Yb-doped KGd(PO(3)), a noncentrosymmetric laser host which possesses second-order nonlinear susceptibility, were grown using the top seeded solution growth slow-cooling (TSSG-SC) technique, reaching a maximum ytterbium concentration in the crystal of approximately 3.2x10(20) at/cm(3). In order to evaluate the potential for self-frequency doubling, the dispersion of the refractive indices of KGd(PO(3))(4) was studied and Sellmeier equations were constructed which are valid in the visible and near-infrared. The Stark splitting of the two electronic states of ytterbium was determined from absorption and emission measurements at room and low temperatures, and this allowed to compute the emission cross sections at room temperature. The fluorescence decay time is quite long, 1.22+/-0.01 ms. Laser generation in the 1 mum range is demonstrated with this new Yb host for the first time. Although the maximum output power achieved, of the order of 100 mW, was limited by the available crystal size and doping level, the more than 55% slope efficiency obtained with this first sample is rather promising for the future.