Wolfe, Daniel B.Conroy, Richard S.Garstecki, PiotrMayers, Brian T.Fischbach, Michael A.Paul, Kateri E.Prentiss, MaraWhitesides, George M.2019-10-032004Wolfe, D. B., R. S. Conroy, P. Garstecki, B. T. Mayers, M. A. Fischbach, K. E. Paul, M. Prentiss, and G. M. Whitesides. 2004. “Dynamic Control of Liquid-Core/Liquid-Cladding Optical Waveguides.” Proceedings of the National Academy of Sciences 101 (34): 12434–38. https://doi.org/10.1073/pnas.0404423101.0027-84240744-28311091-6490http://nrs.harvard.edu/urn-3:HUL.InstRepos:41467507This report describes the manipulation of light in waveguides that comprise a liquid core and a liquid cladding (liq/liq waveguide). These waveguides are dynamic: Their structure and function depend on a continuous, laminar flow of the core and cladding liquids. Because they are dynamic, they can be reconfigured and adapted continuously in ways that are not possible with solid-state waveguides. The liquids are introduced into the channels of a microfluidic network designed to sandwich the flowing core liquid between flowing slabs of the cladding fluid. At low and moderate Reynolds numbers, flow is laminar, and the liq/liq interfaces are optically smooth. Small irregularities in the solid walls of the channels do not propagate into these interfaces, and liq/liq waveguides therefore exhibit low optical loss because of scattering. Manipulating the rate of flow and the composition of the liquids tunes the characteristics of these optical systems.en-USJournal Article2019-10-0310.1073/pnas.0404423101