A Ho:YAG crystal laser is disclosed which is doped with less than 2%
holmium to reduce the lasing threshold and up-conversion, thereby
increasing the operating efficiency of the laser. The laser does not need
sensitizer ions so energy mismatches introduced by the sensitizer ions
ale eliminated to the thereby increase the efficiency of the laser while
minimizing detrimental thermal loading in the laser caused by
up-conversion loss processes. The Ho:YAG crystal laser is directly pumped
by a Thulium fiber laser at 1.9 .mu.m at the holmium .sup.5I.sub.7 to
.sup.5I.sub.8 transition to produce an output at 2.1 .mu.m yielding a
very low quantum defect. The laser is embodied as a thulium fiber laser
pumped oscillator or an amplifier.