Fluorescent Liquid-Core/Air-Cladding Waveguides TowardsIntegrated Optofluidic Light Sources

摘要

The waveguides and light sources are essential building blocks in optofluidics. Here, we have developed the newapproach to fabricate efficient waveguides and light sources by using two-phase stratified flow of dye containing liquidand air. The liquid-core/air-cladding (LA) waveguide can overcome some of major drawbacks of the liquid-core/liquid-cladding (L~2) waveguide without losing its unique advantages. Specifically, stronger optical confinement, originatedfrom the large refractive index contrast between core and cladding, enable us to achieve lower propagation losses andlarger captured fractions (the amount of light to be coupled into the liquid core). In addition, the LA waveguides are freefrom diffusional mixing of the core and cladding fluids. The fluorescent LA waveguides can be fabricated byconventional poly(dimethylsiloxane) (PDMS) based soft lithography, which is compatible with the other parts ofoptofluidic devices. Therefore, the fluorescent LA waveguide can be easily integrated with precise alignment as aninternal light source of optofluidic devices.