Measuring flow velocity distribution in microchannels using molecular tracers

We demonstrate the capability of a molecular tracer based laser induced fluorescence photobleaching anemometer for measuring fluid velocity profile in microfluidics. To validate the feasibility and accuracy of this measurement system, the velocity profiles of the cylindrical and rectangular microchannels are measured, respectively. We compare our experimental results with theoretical prediction. The theoretical prediction shows a good consistency with practical measurement results. The spatial resolutions are analyzed and validated. Finally, the error source of the presented system is analyzed, which makes it possible to compensate some error quantitatively and guides the application of this system.