Multiwavelength, Ultranarrow Line Width Emission from Fiber-Capillary-Integrated Colloidal Quantum Well Lasers

Multiwavelength laser sources are indispensable in the development of quantum information, laser lighting, and laser display technologies. However, conventional multiwavelength lasers are costly, cumbersome, and intricate, limiting their adaptability across various applications. To overcome these challenges, we propose an integrated multiwavelength laser source based on solution-processed colloidal quantum wells (CQWs). Through precise control over size, elemental doping, and the design of heterostructures, we have engineered CQWs that exhibit ultralow stimulated emission thresholds across red, orange, yellow, and green wavelengths. CQW-based multiwavelength laser source delivers single-mode lasing with narrow line widths below 50 pm. Importantly, the laser structure is optimized via optical fiber coupling strategies, eliminating the need for complex micromanipulation procedures. Furthermore, we provide a preliminary demonstration of the applications of CQW-optical fiber lasers in automobile exhaust sensing, confirming their great promise for further development. These impressive specifications for colloidal semiconductor lasers highlight their strong potential as a powerful platform for next-generation visible light laser technologies.