USING NUCLEAR SPINS, RADIO-WAVES, SODIUM ATOMS, AND LASER-LIGHT TO INVESTIGATE SPATIOTEMPORAL NONLINEAR-SYSTEMS

Within the wide field of nonlinear dynamics we investigate temporal an d spatial behavior of electromagnetic systems. A strange type of laser , the nuclear magnetic resonance (NMR) laser, shows truly chaotic beha vior and is therefore ideally suited to analyze experimentally and the oretically a variety of temporal nonlinear effects. Of particular inte rest is the analysis of its strange attractors in terms of unstable pe riodic orbits, For the extension of our research from the NMR laser (r epresenting a purely temporal system described by the Bloch-Kirchhoff ordinary differential equations) to spatial and spatiotemporal systems , we chose, as a three-dimensional dynamic system, polarized laser bea ms interacting nonlinearly with sodium atoms. Among other effects, we have observed beam bouncing, beam splitting, and beam switching. This can be well described by partial differential equations for beam propa gation derived from the Schrodinger equation and the Maxwell equations . An intuitive explanation is given in terms of intensity and polariza tion patterns formed by optical-pumping-induced mutual refractive inde x modifications between polarized resonant laser beams.