Resonantly diode-pumped Ho3+:Y2O3 ceramic 2.1 µm laser.

We report what is believed to be the first laser operation based on Ho3+-doped Y2O3. The Ho3+:Y2O3 ceramic was resonantly diode-pumped at ~1.93 µm to produce up to 2.5 W of continuous wave (CW) output power at ~2.12 µm. The laser had a slope efficiency of ~35% with respect to absorbed power and a beam propagation factor of M2 ~1.1. We have measured the absorption and stimulated emission cross sections of Ho3+:Y2O3 at 77 K and 300 K and present the calculated gain cross section spectrum at 77 K for different excited state inversion levels.