Optofluidic out-of-plane interferometer

We present a Rayleigh interferometer with a novel optofluidic retarder, using precisely controlled and mixed fluids that vary the optical path length in one arm. The retarder is built as a PDMS device, including on chip mixing of the retardation liquid. The out-of-plane geometry facilitates the inclusion in generic optical systems, and presents a major advantage over traditional in-plane optofluidics. To our knowledge this is the first device using out-of-plane optofluidics to manipulate light for interferometry applications.