Ultralow-threshold electrically pumped quantum-dot photonic-crystal nanocavity laser

Efficient, low-threshold and compact semiconductor laser sources are under investigation for many applications in highspeed communications, information processing and optical interconnects. The best edge-emitting and vertical-cavity surface-emitting lasers have thresholds on the order of 100 mu A (refs 1,2), but dissipate too much power to be practical for many applications, particularly optical interconnects(3). Optically pumped photonic-crystal nanocavity lasers represent the state of the art in low-threshold lasers(4,5); however, to be practical, techniques to electrically pump these structures must be developed. Here, we demonstrate a quantum-dot photonic-crystal nanocavity laser in gallium arsenide pumped by a lateral p-i-n junction formed by ion implantation. Continuous-wave lasing is observed at temperatures up to 150 K. Thresholds of only 181 nA at 50 K and 287 nA at 150 K are observed-the lowest thresholds ever observed in any type of electrically pumped laser.