Efficient blue lasers based on gain structure optimizing of vertical-external- cavity surface-emitting laser with second harmonic generation

摘要

We report on the demonstration of highly efficient blue lasers based on intracavity frequency doubling vertical-external-cavity surface-emitting lasers (VECSELs). By optimizing the number of InGaAs quantum wells and employing Al_(0.3)Ga_(0.7)As carrier blocking layers in resonant periodic gain structures, we observed the pump-power-limited output power of 4.5 W at 920 nm for an InGaAs/GaAs quantum well VECSEL. With a frequency doubling LiB_3O_5 crystal inside the cavity, 1.9 W continuous-wave 460 nm blue output was demonstrated. Power conversion efficiencies (=output power/pump input power) of 22.5% and 9.5% are realized for λ ～ 920 nm and λ ～ 460 nm, respectively.