Continuous-Wave Pumped Self-Assembled Colloidal Topological Lasers.

The field of optoelectronic integrated circuits is actively developing reliable and efficient room-temperature continuous-wave (CW) lasers. CW-pumped lasers combine the economical and simple manufacturing processes of colloidal semiconductor lasers with the efficient and stable output of continuous pumping, enabling them to significantly impact the field of semiconductor lasers. However, development is still severely challenged by limitations such as gain materials and cavity structures. Consequently, as a compromise, most colloidal semiconductor lasers proposed to date have relied on another pulsed laser as the pumping source. In this study, a self-assembled colloidal topological laser is proposed that benefits from CW pumping at room temperature. By utilizing an interfacial self-assembly strategy, nanoplatelets (NPLs) are managed to control the collective orientation (face-down or edge-up), achieving controlled polarization of amplified spontaneous emission for the first time. Furthermore, precise control over the thickness of a single NPL layer is demonstrated, which enables the laser system to offer extensive wavelength tunability (over 50 nm), ultra-high polarization (over 95%), and good temporal stability. These metrics signify the optimal performance level of colloidal semiconductor lasers, marking a new era in solution processing systems for the optoelectronic integrated circuit field.