Characterization and comparison of 1% at Yb-doped Lu2O3 and Sc2O3 ceramics as laser gain media

We present the first laser oscillation achieved on Yb-doped Sc2O3 and Lu2O3 ceramics with a level of doping as low as 1 at %, under quasi-continuous wave pumping at 968 nm. Ceramic samples reached comparable performances in terms of tunability ranges, which exceeds 41 nm, and laser output powers. In particular, with the former sample emitting at 1040.5 nm we measured a maximum output power of 2.2 W with a corresponding slope efficiency of eta = 59%. The latter medium delivered 1.8 W with a slope of eta = 45% at 1032.5 nm while at 1078 nm we measured 1.5 W with eta = 34%. Finally, we report the measured level of the Amplified Spontaneous Emission (ASE) for both samples, which was found to be less than 0.1 mW at the maximum pump power.