Lee Wonsuk, Luo Yunhan, Zhu Qiran, Fan Xudong
Department of Biomedical Engineering, University of Michigan, 1101 Beal Ave., Ann Arbor, MI 48109, USA.
Opt Express. 2011 Sep 26;19(20):19668-74. doi: 10.1364/OE.19.019668.
We develop a novel nL-sized microdroplet laser based on the capillary optofluidic ring resonator (OFRR). The microdroplet is generated in a microfluidic channel using two immiscible fluids and is subsequently delivered to the capillary OFRR downstream. Despite the presence of the high refractive index (RI) carrier fluid, the lasing emission can still be achieved for the droplet formed by low RI solution. The lasing threshold of 1.54 µJ/mm(2) is achieved, >6 times lower than the state-of-the-art, thanks to the high Q-factor of the OFRR. Furthermore, the lasing emission can be conveniently coupled into an optical fiber. Finally, tuning of the lasing wavelength is achieved via highly efficient fluorescence resonance energy transfer processes by merging two different dye droplets in the microfluidic channel. Versatility combined with improved lasing characteristics makes our OFRR droplet laser an attractive platform for high performance optofluidic lasers and bio/chemical sensing with small sample volumes.
我们基于毛细管光流体环形谐振器（OFRR）开发了一种新型的纳升尺寸微滴激光器。微滴在微流控通道中通过两种不混溶的流体产生，随后被输送到下游的毛细管OFRR中。尽管存在高折射率（RI）载液，但由低RI溶液形成的液滴仍可实现激光发射。由于OFRR的高品质因数，实现了1.54 µJ/mm(2)的激光阈值，比现有技术低6倍以上。此外，激光发射可以方便地耦合到光纤中。最后，通过在微流控通道中合并两个不同的染料微滴，通过高效的荧光共振能量转移过程实现了激光波长的调谐。多功能性与改进的激光特性相结合，使我们的OFRR微滴激光器成为用于小样本体积的高性能光流体激光器和生物/化学传感的有吸引力的平台。
