High-power in-band pumped Er : YAG laser at 1617 nm

High-power room-temperature operation of an Er:YAG laser at 1617 nm in-band pumped by a cladding-pumped Er, Yb fiber laser at 1532 nm is reported. The Er: YAG laser yielded 31 W of continuous-wave output in a beam with M-2 approximate to 2.2 for 72 W of incident pump power. The threshold pump power was 4.1 W and the slope efficiency with respect to incident pump power was similar to 47 %. The influence of erbium doping level and resonator design on laser performance is discussed, and the prospects for further increase in output power and improvement in lasing efficiency are considered. (C) 2008 Optical Society of America.This work was funded by the Electro-Magnetic Remote Sensing (EMRS) Defence Technology Centre, established by the UK Ministry of Defence