Embedding liquid lasers within or around aqueous microfluidic droplets

作者：Zheng Lu; Zhi Min; Chan Yinthai; Khan Saif A^*

来源：Lab on a Chip, 2018, 18(1): 197-205.

DOI：10.1039/c7lc00701a

In this paper, we demonstrate the incorporation of dye-based liquid lasers within or around flowing aqueous microfluidic droplets. In particular, we use dye solutions in benzyl alcohol, and either disperse an ensemble of small (similar to 20 mu m) lasing droplets within large (similar to 500 mu m) aqueous droplets flowing in a simple glass capillary-based microfluidic device, or 'wrap' a thin (similar to 10 mu m) lasing benzyl alcohol shell around larger (similar to 560 mu m) microfluidic aqueous droplets. We experimentally and theoretically characterize the lasing behavior in both cases, which is supported by whispering-gallery mode (WGM) optical resonances at the droplet interfaces. We showcase a simple application of our method, which highlights the advantages of having embedded, spatially segregated laser sources within a droplet containing a model analyte solution. With this method, each microfluidic droplet now functions not only as an isolated experiment flask, but is also capable of on drop sensing that exploits WGM-based lasing, thus expanding the possibilities for online monitoring of biophysical/biochemical processes and sensitive detection of biomolecules in droplet-based microfluidics.

• 出版日期2018-1-7