Optical pumping of quantum dot micropillar lasers

Arrays of quantum dot micropillar lasers are an attractive technology platform for various applications in the wider field nanophotonics. Of particular interest is potential efficiency enhancement as consequence cavity electrodynamics effects which makes them prime candidates next generation photonic neurons neural network hardware. However, optical pumping their power-conversion can be very low. Here we perform in-depth experimental analysis microlasers and investigate input-output relationship over a wide range conditions. We find that current energy limitation caused by disadvantageous concepts low exciton conversion efficiency. Our results indicate non-resonant into GaAs matrix (wetting layer), 3.4% (0.6%) pump converted lasing-relevant excitons, those only 2% (0.75%) provide gain to lasing transition. Based on our findings propose improve orders magnitude increasing aluminium content AlGaAs/GaAs mirror pairs upper Bragg reflector.