Non-linear dynamics of the electro-optic response of confined liquid crystals

We have experimentally studied the electro-optic response of two different. classes of systems consisting of a nematic liquid crystal either dispersed into a solid polymer matrix or mixed with aggregated silica particles forming a random gel network. By monitoring the time evolution of the optical transparency of the system under che action of electric field pulses, we have found that the response times depend in an intriguing and non-monotonic fashion on the field strength. We show that the observed nonlinear behavior can be interpreted by a simple visco-elastic model of the liquid crystal domains combined with an accurate description of their light scattering cross-section.