Spectroscopic and lasing properties of highly-doped Ytterbium-glasses

Abstract

Ytterbium (Yb) doped glass is expected as next generation high-performance solid laser material. However, the laser glasses have a problem that the ions-doping-concentration is much lower than crystals. In this study, we make highly-doped Ytterbium-ions glasses (YbF 3 -BaF 2 -AlF 3 -GeO 2 , YbBAG), and succeeded laser oscillations of 20 mol.% Ytterbium-ions glass. The highly-doped Ytterbium-ions glasses are much suitable for short-fiber or waveguide lasers. 1.IntroductionRecently, Ytterbium-ions doped gain materials [1] are known to be suitable for high-efficiency, high-power, continuous-wave or short-pulse lasers with compact structures. For example, several kW with nearly-single-transverse-mode output power was achieved in continuos-wave oscillation, kW-average power was also achieved in ultrashort-pulse oscillation. Ultrashort-pulse generations around several-ten fs were also achieved by many of the laser gain materials, ultrashort-pulse generation toward the fluorescence spectrum limit were achieved by intracavity nonlinear medium [2-3], high-optical to optical conversion efficiencies around 80% [4] and around 70% [5] were achieved in continuous-wave and nano-second pulsed oscillations, respectively. The highest quantum efficiency above 99% was also obtained [6]. Although for the case of the laser crystals, the high ions-doping-concentration is up to 100%, i.e. YbAG (100 at.% Yb :YAG), KYbW (100 at.% Yb :KYW) are exists already, and the pump absorption length are much shorter than sub-mm. however, for the case of the laser glasses, the ions-doping-concentration was much low compared to the crystals and the length of the gain fiber or waveguide was much longer than several-cm because of the pump absorption length was much longer than several-cm. IQEC/CLEO Pacific Rim