Spatial coherence of laser radiation transmitted by a liquid crystal near its phase transition to the isotropic liquid state

The spatial coherence of the radiation transmitted by a thin liquid-crystal layer of MBBA near its phase transition was measured very accurately. A laser beam (λ=0.633 μ) was scattered at a small angle from this layer. Attention was concentrated on the heterogeneous state in which the nematic and isotropic phases of the liquid crystal coexisted. The intensity of zero-angle scattering was determined. The dependence of the coherence radius of the transmitted radiation on the liquid crystal temperature was determined. The characteristics of a phase transition of a liquid crystal in a thin cell were analyzed.