of doping as low as 1 at %, under quasi-continuous wave pumping at 968 nm. Ceramic samples reached com-
parable 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 corre-
sponding slope efficiency of
= 59%. The latter medium delivered 1.8 W with a slope of = 45% at 1032.5 nm while at 1078 nm we measured 1.5 W with
= 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.