  We have investigated the bleaching dynamics that occur in optofluidic dye
lasers where the liquid laser dye in a microfluidic channel is locally bleached
due to optical pumping. We find that for microfluidic devices, the dye
bleaching may be compensated through diffusion of dye molecules alone. By
relying on diffusion rather than convection to generate the necessary dye
replenishment, our observation potentially allows for a significant
simplification of optofluidic dye laser device layouts, omitting the need for
cumbersome and costly external fluidic handling or on-chip microfluidic pumping
devices.
