An optically pumped InGaAsP/InP quantum dot rolled-up microtube laser

Rolled-up quantum dot microtubes are a promising candidate for light sources in integrated photonics. We have fabricated InGaAsP/InAs quantum dot rolled-up microtubes from InGaAsP strained bilayers with embedded InAs quantum dots (grown by chemical beam epitaxy). In room-temperature photoluminescence experiments we have observed resonant-mode emission with wavelengths in the telecom range. This resonant emission is consistent with whispering gallery modes. At a temperature of 82 K, we have demonstrated multi-mode lasing under continuous wave optical pumping. We estimate an ultra-low lasing threshold near 1.25 $\mu$Ws of absorbed optical power.