Three-dimensional numerical prediction of domain walls in class-A ring lasers

摘要

We carefully numerically simulate the full three-dimensional (3D), two-levelMaxwell Bloch equations in a ringnconfiguration, beyond the rotating wave and slowly varying envelope approximations. The 3D electromagneticnspatial and temporal variations are then well described up to the micrometer and femtosecond scales. Genuinendielectricwaveguide boundary conditions together with no-reflection, perfectly matching layers are implemented.nBesides the already known and well-described transverse instabilities of a traveling-wave solution, we observensteady zipper-state configurations characterized by the coexistence, in the laser transverse plane, of twonlongitudinal counter-propagating waves, with their separation plane parallel to the ring laser optical axis. Thendirection of propagation of the traveling wave is observed to change slowly and periodically with time.