Order-parameter fluctuations of a lyotropic liquid crystal in the nematic and isotropic phases

Abstract
We show, both through theory and light-scattering experiments, how the order-parameter fluctuations in a nematic liquid crystal can be decomposed into two parts: a critical part consisting of fluctuations in the magnitude of the order and a noncritical part, the well-known director fluctuations. Mean-field theory is shown to predict some new and interesting relations between these two components, most of which are confirmed by experiment.