Wetting-Layer-Pumped Continuous-Wave Surface-Emitting Quantum-Dot Laser

Quantum-dot vertical-external-cavity surface-emitting lasers (QD VECSELs) are of interest due to their large inhomogeneous gain spectrum and the potential for temperature insensitivity and low threshold. We report a QD VECSEL which is wetting-layer-pumped using a 915-nm diode laser, reducing the quantum defect compared to barrier pumping. A slope efficiency of 56% relative to absorbed pump power was measured from an unprocessed sample with a heat-sink temperature of -30 °C, 1.75 × higher than when barrier pumped using an 830-nm pump diode.