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

Abstract

Efficient, low-threshold and compact semiconductor laser sources are under investigation for many applications in high-speed communications, information processing and optical interconnects. The best edge-emitting and vertical-cavity surface-emitting lasers have thresholds on the order of 100 µA (refs 1, 2), but dissipate too much power to be practical for many applications, particularly optical interconnects (Miller in Proc. IEEE 97:1166, 2009). Optically pumped photonic-crystal nanocavity lasers represent the state of the art in low-threshold lasers (Loncar et al. in Appl. Phys. Lett. 81:2680, 2002, Noda in J. Opt. Soc. Am. B 27:B1, 2010); 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.