Realisation and characterisation of all liquid optical waveguides

We here report on the realisation of all liquid optical waveguides (ALOW). To our knowledge this is the first report in the literature on this topic. ALOWs are fluidic structures with waveguiding properties. They are realised in flow channels or tubes under laminar flow conditions, i.e. at moderate Reynolds numbers. The ALOW consists of an annular flow of two liquids, where the centre core liquid has a higher refractive index than the surrounding cladding liquid. The main applications for ALOWs are in optical detection.