  A simple method was developed to observe the interference patterns of the
light reflected by the interfaces of thin liquid films. Employing a fluorescent
microscope with epi-illumination, we collected the 2D patterns of interference
fringes containing information of the liquid film topography at microscale. To
demonstrate the utility of the proposed visualization method we developed a
framework for reconstructing the profiles of liquid films by analysing the
reflected interferograms numerically. Both the visualization and reconstruction
methods should be useful for variety of microfluidic applications involving the
flows with droplets and bubbles in which the knowledge of the topography of the
interfacial liquid film is critical.
