We present an optical, noninvasive and label-free approach to characterize flow profiles in microfluidic devices. Coherent anti-Stokes Raman scattering signals were used to map the mass transport in a microfluidic device that was then related back to the local flow rate of dilute solutes having constant fluid properties. Flow characterization was demonstrated in two common types of microfluidic devices, polydimethylsiloxane/glass square channels and wet-etched glass tapered channels.

Opt. Lett.

Schafer, D., Müller, M., Bonn, M., Marr, D. W. M., van Maarseveen, J., & Squier, J. (2009). Coherent anti-Stokes Raman scattering microscopy for quantitative characterization of mixing and flow in microfluidics. Opt. Lett., 34, 211–213. doi:10.1364/OL.34.000211