Efficient laser operation of Yb3+ : Sc2O3and spectroscopic characterization of Pr3+ in cubic sesquioxides

Yttria (Y 2 O 3 ), the isostructural scandia (Sc 2 O 3 ), and lutetia (Lu 2 O 3 ) exhibit a very high thermal conductivity of 15.5 W/mK in Scandia and 12.2 W/mK in Lutetia (measured at 50°C). An Yb(6.5 x 10 20 cm -3 ): Sc 2 O 3 doped crystal showed efficient laser operation when pumped with a Ti-sapphire laser at 941 nm. A maximum output power of 970 mW at 1041 nm was obtained with approximately 1.85 W of incident power. Samples doped with Praseodymium exhibit no emission from the 3 P j levels. All fluorescence emission can be assigned to the 1 D 2 -level. A possible reason for the complete absence of emission from the 3 P j levels could be a direct energy transfer to the conduction band of the host crystal.