Figure 2: Function of L2 waveguides
Liquid streams containing red, blue and green fluorescent dyes flow in the laminar regime in a microchannel. They are separated from each other by a low-index liquid (yellow), thus forming L2 waveguides (top-left). White light illumination of the channel (top-right) results in generation of fluorescent light of three different colors within each waveguide. This light exits at the T-split, where the waveguides are bent at an angle that is too sharp to maintain guiding. The output can be visualized by a color CCD camera focused at the end of the channel (bottom-left).