Cascade Er:YAG pulsed lasers at room temperature.

Cascaded mid-infrared (MIR) pulsed laser output in Er:YAG crystals at room temperature is achieved experimentally. The existence of a cascade at room temperature in Er:YAG crystals is confirmed. Furthermore, the effect of the cascade on MIR laser performance is studied. With the assistance of the cascade, the thresholds are reduced by 13.3% and 12.5%, and the slope efficiencies are increased by 3.2% and 12.3% compared to a non-cascade configuration in 10 and 15 at.% Er:YAG, respectively. The excited-state absorption is considered to be the mechanism responsible for the laser performance optimization. This Letter should be helpful for the improvement of erbium-doped 3 µm laser output energy.