Room-temperature continuous-wave lasing in GaN/InGaN microdisks

Microdisk lasers feature low-loss, high-quality whispering gallery modes1,2,3 that offer the potential for ultralow-threshold lasing4,5,6,7 that is not limited by challenges in mirror fabrication. Here we report fabrication and optical measurements of GaN-based microdisk lasers with a very low threshold of 300 W cm−2—orders of magnitude lower than any previous GaN microdisk laser. This is also the first report of room-temperature, continuous-wave (CW) lasing in a GaN microdisk.