HOMOCLINIC PHENOMENA IN OPTOTHERMAL BISTABILITY WITH LOCALIZED ABSORPTION

Time dynamics of a family of opto-thermal nonlinear devices is describ ed by means of a system of linear partial differential equations subje cted to a nonlocal and nonlinear boundary condition and a rich variety of homoclinic phenomena is numerically found. Linear-stability analys is shows that the effective dynamical dimension is determined by the d evice structure, i.e. by the number of layers between two mirrors, and then it may be easily varied. A variety of local and global bifurcati ons observed in bilayer systems are described in detail, showing that the dynamics is in effect two-dimensional except for subtle features a ppearing in a gluing bifurcation where two homoclinic connections occu r almost simultaneously. Complex behaviour is shown to occur in the ca se of trilayer systems, with a very similar dynamics to the one of the well-known Rossler model of third-order ordinary differential equatio ns. Two different families of aperiodic phase portraits are described in detail and their association with homoclinic connections to saddle invariant sets of different configurations is pointed out. The occurre nce of complex dynamics is demonstrated by means of first-return 1D ma ps obtained in proper Poincare sections.