Nonlinear Properties of Novel Glass-Ceramics with Co2+ :Ga2O Nanocrystals

Transparent glass-ceramics containing y-Ga2O3:Co2+ nanocrystals are synthesized. Their structure, absorption, absorption saturation and bleaching relaxation of Co2+ ions are studied. Passive Q-switching of diode-pumped Er,Yb: glass laser is realized with the developed glass-ceramics. Crystals with Co2+ ions in tetrahedral sites are of practical interest due to their saturable absorption at around 1.5 Rm. Co2+-doped materials are used for passive Q-switching of erbium (Er) eye-safe lasers emitting in the vicinity of this wavelength. In the present paper we report on the optical and nonlinear properties of glass-ceramics with y-Ga203:Co2+ nanocrystals with the possible use as saturable absorbers of 1.5-1.7 Rm Er lasers. Glass-ceramics were prepared from the Li2O Ga2O3 SiO2 precursor glass doped with 0.1 mol% CoO (Loiko PA, Dymshits OS, Vitkin VV, Skoptsov NA, Kharitonov AA, Zhilin AA, Alekseeva IP, Zapalova SS, Malyarevich AM, Glazunov IV, Yumashev KV Laser Phys Lett 12:035803-1-5, 2015). The precursor glass was heat-treated at the temperatures of 680-800 C for 6 h resulting in the precipitation of nanosized cubic crystals of y-Ga203. The crystal size of y-Ga203 was changed from about 7-20 nm as the heat treatment temperature increased from 680 to 800 degrees C. A Transmission Electron Microscopy (IBM) image of the powdered glass-ceramics sample heat-treated at 730 degrees C is shown in Fig. 69.1a.