Numerical study of optically induced director oscillations in nematic liquid crystals: Transition to chaos via homoclinic gluings and the role of backflow

We investigate the director oscillations of a homeotropically aligned nematic liquid crystal that are generated by cw laser radiation incident at a slightly oblique angle. The full nematodynamic equations are solved numerically, and it is shown that the inclusion of backflow leads to a qualitative change of the theoretical bifurcation scenario at moderate to high intensities. Very good correspondence is achieved with recent observations. The route to chaos via a sequence of homoclinic gluing bifurcations, whose existence was suggested by simple models, but doubted by recent calculations and experiments, is shown to exist in a parameter region unexplored by experiments.