Pattern formation in an excitable liquid crystal system

We theoretically demonstrate that a nematic liquid crystal in a Fabry-Perot interferometer to be an excitable system. The excitability is shown to arise from the competition of two Kerr type nonlinearities resulting from field-induced molecular reorientation and thermal absorption in the presence of the laser radiation. We have observed all the essential features of excitability in this system when it is spatially extended, namely, propagating pulses in one-dimensional space and spiral waves in two dimensions. We have further studied patterns resulting from random noise excitations in this liquid crystal system.