Polarization chaos in a vector nonautonomous class-A laser

We investigate the dynamics of a vector (weakly anisotropic) class-A laser subjected to the modulation of the resonator anisotropy directions. We report on polarization symmetry breaking and, to our knowledge, this is the first explicit example of chaos affecting amplitude and polarization parameters of the field emitted by a laser in which material dynamics is not essential. The physical mechanism of the chaotic behaviour is discussed.