Fig. 1. Colloidal quantum dot lasers based on self-assembly methods. (a) CQD random laser^[31]; (b) CQD microplate laser^[15]; (c) CQD microsphere laser^[34]; (d) CQD microdisk laser^[33]

Fig. 2. Colloidal quantum dot lasers based on micro/nano etching method. (a) Schematic of a CQD/SiN microdisk laser^[18]; (b) optical microscopy image and scanning electron microscopy images of the CQD/SiN microdisks^[18] (Top is an optical microscopy image of the CQD/SiN microdisks, middle is a top view SEM image of a CQD/SiN microdisk, bottom is a SEM image of a sectional view of a CQD/SiN microdisk); (c)

Fig. 3. CQD lasers based on a pattern-assisted method. (a) SEM image of a CQD plasmonic cavity^[24]; (b) spectrum of a CQD spaser(inset is an optical image of the spaser above the pump threshold)^[24]

Fig. 4. CQD lasers based on a pattern-assisted method. (a) Atomic force microscopy image of a CQD microdisk^[36]; (b) SEM image of a sectional view of a CQD microdisk^[36]; (c) dark-field optical image of a waveguide-ring resonator (WRR)^[14]; (d) SEM image of a sectional view of a CQD WRR^[14]; (e) spectra of

Fig. 5. On-chip integration of CQD lasers. (a) Dark-field image of a coupling structure of the CQD WRR with multiple functional devices^[14]; (b) optical image corresponding to Fig. (a) above the pump threshold^[14]; (c) dark-field optical image of the tangential coupling structure with two CQD microdisks and one silver nanowire^[36]; (d) optical image corres