Excitability and pattern formation in a liquid crystal Fabry-Perot interferometer

We demonstrate a nonlinear Fabry-Perot interferometer with a nematic liquid crystal to be an optical excitable system. The excitability is shown to ar ise from the competition of two Kerr type nonlinearities resulting from fie ld-induced molecular reorientation and thermal absorption in the presence o f laser radiation. We have observed all the essential fractures of excitabi lity in this system when it is spatially extended, namely, propagating puls es in one-dimensional space and spiral waves in two dimensions. We have fur ther studied patterns resulting from random noise excitations in this syste m. (C) 2001 Elsevier Science B.V. All rights reserved.