Microsphere biolasers have attracted a great deal of interest due to their potential for biosensing and cell tracking. Here we demonstrate a novel, to the best of our knowledge, microfluidic-based fabrication of nearly monodisperse dye-doped protein microsphere biolasers with a tunable size from 150 to 50 µm. In particular, for an 85 µm-bead, about 70% of the fabricated microspheres have the same size of 85 µm. Under optical pumping, the fabricated microspheres emit whispering gallery mode lasing emission with a lasing threshold of ${{7}}\;\unicode{x00B5} {\rm{J}}\;{{\rm{mm}}^{- 2}}$ and quality ($\!Q$) factor up to 3000. Interestingly, microspheres with the same size exhibit a similar lasing threshold and spectrum. The result indicates a high reproducibility of microsphere biolasers by the microfluidic-based fabrication technique. This Letter provides an effective method for mass production of high-$Q$ factor microsphere biolasers which is a significant step toward real biosensing and medical applications.

中文翻译：

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单分散和尺寸可调的高质量因子微球生物激光器

微球生物激光器因其在生物传感和细胞追踪方面的潜力而引起了极大的兴趣。在这里，我们展示了一种新颖的，据我们所知，基于微流体的几乎单分散染料掺杂的蛋白质微球生物激光器的制造，其可调尺寸从 150 到 50 µm。特别是，对于 85 µm 珠，大约 70% 的制造微球具有相同的 85 µm 尺寸。在光泵浦下，制造的微球发出回音壁模式激光发射，激光阈值为${{7}}\;\unicode{x00B5} {\rm{J}}\;{{\rm{mm}}^{ - 2}}$和质量（$\!Q$) 因子高达 3000。有趣的是，具有相同尺寸的微球表现出相似的激光阈值和光谱。结果表明，基于微流体的制造技术可实现微球生物激光器的高重现性。这封信提供了一种大规模生产高Q$因子微球生物激光器的有效方法，这是迈向真正的生物传感和医学应用的重要一步。