Whispering gallery mode lasing in electrically driven quantum dot micropillars

We report on whispering gallery mode lasing in electrically driven quantum dot micropillar cavities. The high quality microcavity structures feature whispering gallery mode emission with Q-factors up to 40 000 and laser threshold currents below 10 μA for devices with diameters between 2.6 and 5.6 μm. For large diameter micropillars a coexistence of lasing from two whispering gallery modes is realized which could be the basis for efficient terahertz generation via difference frequency generation.