Effects of Ho3+-doping concentration on the performances of resonantly pumped Ho:YAG ceramic lasers

Abstract In this paper we report on efficient lasing of a polycrystalline Ho:YAG ceramics at ∼2.1 μm in-band pumped (5I8 → 5I7) by a Tm:fiber laser and discuss the effects of Ho3+-doping concentration on laser performances. Lasing characteristics of 0.8 at.%, 1.0 at.%, 1.5 at.%, 2.0 at.% and 4.0 at.% Ho3+-doped ceramic samples were evaluated and compared. Using an output coupler of 6% transmission, 9.4 W of output power at 2097 nm was generated with the 0.8 at.% doped Ho:YAG ceramic under 15.1 W of pump power, corresponding to a slope efficiency with respect to incident pump power of 64.0%. The prospects for improvement in output power and lasing efficiency via further optimization in Ho3+-doping concentration are considered.