Slowing down of molecular rotation at the smectic-A→smectic-C/emph>transition of liquid crystals

Abstract
We report the first observation of the slowing down of molecular rotation around the long axis in the smectic-A phase of a ferroelectric liquid crystal. This effect, evidenced by degenerate four-wave mixing, is interpreted in terms of cooperative orientation of the transverse molecular axes, due to a coupling between the fluctuating ferroelectric order and the transient biaxial mode induced by the laser fields.