Efficient cryo-cooled 2.7-μm Er3+:Y2O3 ceramic laser with direct diode pumping of the upper laser level

Reported here is the first cryogenically-cooled performance of Er 3+ -doped Y 2 O 3 laser based on 4 I 11/2 → 4 I 13/2 transitions. Laser material was diode-pumped directly into an upper laser manifold 4 I 11/2 in order to minimize quantum defect of this Mid-IR laser. CW output power of over 1.6 W at ∼ 2.7 μm was achieved with the 27.5% slope efficiency, which is approaching the quantum defect-limited efficiency value despite the marginal optical quality of the available laser sample.