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

In this paper we report on efficient lasing of a polycrystalline Ho:YAG ceramics at similar to 2.1 mu m in-band pumped (I-5(8) -> I-5(7)) 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. (C) 2012 Elsevier B.V. All rights reserved.