Polarization pulsations in lasers represent one of the simplest forms of coupled mode dynamics and have led to the study of increasingly complex forms of field-atom interactions. Research under this RUI grant will conduct detailed experimental studies of a coupled mode polarization-isotropic standing wave laser in which the two modes have the same spatial pattern and same frequency and differ only in the polarization of the electromagnetic fields. In the absence of symmetry breaking, recently developed models predict new types of behavior (depending on laser parameters) such as: a) bistability between the two modes; b) pulsations in the total laser intensity; c) more complex and partially anticorrelated pulsations between the two modes. Experiments will be initiated with 3.39 micron He-Ne lasers and may be extended to 3.51 micron He-Xe lasers. Measurements will be made on individual phases, phase differences, individual amplitudes, and amplitude changes as a function of adjustments in operating conditions such as gas pressure, gas mixtures, cavity length, cavity losses, and excitation. Using digitized data, the oscillations will be analyzed to determine whether they occur chaotically or are merely random. Theoretical and numerical work, extending or modifying existing models to match conditions, will be used for comparisons with the experimental results and used to predict amplitude and phase dynamics.
