Birefringent Graphene Oxide Liquid Crystals in Microchannel for Optical Switch

We propose a mechanical–hydrodynamical experimental setup in which the microfluidic motion manipulates the optical birefringence of levitated graphene oxide liquid crystal. The birefringence of the sample is changed by flowing graphene oxide liquid crystal in the microchannel. By measuring the ordinary and extraordinary refractive indices at five flow rates, one can determine the value of the birefringence of the samples, precisely. Our results demonstrate that, by adjusting the concentration and flow rate of dispersion of the graphene oxide nanoflakes, the induced birefringence can be controlled. It is also shown that this approach can be used as an optical switch.