Blue lasers play a pivotal role in laser-based display, printing, manufacturing, data recording and medical technologies. Colloidal quantum dots (QDs) are solution-grown materials with strong, tunable emission covering the whole visible spectrum, but the development of QD lasers has largely relied on Cd-containing red-emitting QDs, with technologically viable blue QD lasers remaining out of reach. Here we report on the realization of tunable and robust lasing using low-toxicity blue-emitting ZnSe–ZnS core–shell QDs that are compact in size yet still feature suppressed Auger recombination and long optical gain lifetime approaching 1 ns. These characteristics allow us to handle the blue QDs like laser dyes for liquid-state amplified spontaneous emission and lasing. The blue QD laser is operated under quasi-continuous-wave excitation by solid-state nanosecond lasers. A Littrow-configuration cavity enables narrow linewidth (<0.2 nm), wavelength-tunable, coherent and stable laser outputs without circulating the solution. These results indicate the promise of ZnSe–ZnS QDs to fill the ‘blue gap’ of QD lasers and to replace less stable blue laser dyes for a multitude of applications.

蓝色激光器在基于激光的显示、打印、制造、数据记录和医疗技术中发挥着关键作用。胶体量子点 （QD） 是溶液生长材料，具有覆盖整个可见光谱的强且可调的发射，但 QD 激光器的发展在很大程度上依赖于含 Cd 的红色发射 QD，而技术上可行的蓝色 QD 激光器仍然遥不可及。在这里，我们报告了使用低毒性蓝光发射 ZnSe-ZnS 核壳 QD 实现可调谐和稳健的激光，这些量子点尺寸紧凑，但仍具有抑制的俄歇复合和接近 1 ns 的长光增益寿命。这些特性使我们能够处理蓝色 QD，例如用于液态放大自发发射和激光的激光染料。蓝色 QD 激光器在固态纳秒激光器的准连续波激发下运行。Littrow 配置腔可实现窄线宽 （<0.2 nm）、波长可调、相干和稳定的激光输出，而无需循环溶液。这些结果表明，ZnSe-ZnS QD 有望填补 QD 激光器的“蓝色空白”，并在多种应用中取代不太稳定的蓝色激光染料。