“…[19][20][21][22] Various studies have been conducted to realize low-threshold single-color optical gain for colloidal quantum dots (QDs) and their 2D counterparts, colloidal quantum wells (CQWs). [23,24] Through the integration of these nanomaterials into different optical feedback configurations, such as Fabry-Pérot type cavity, [25] vertical cavity surface emitting laser (VCSEL), [26,27] WGM resonator, [28,29] DFB laser, [30] and single-color colloidal lasers have been demonstrated. Moreover, broadband multicolor amplified spontaneous emission (ASE) and random lasing have been shown using a particular type of colloidal nanocrystals with large core and shell sizes.…”