Unveiling stability of multiple filamentation caused by axial symmetry breaking of polarization

Femtosecond laser filamentation is generally initialized from unpredictable symmetry breaking caused by random noise, causing it to be barely controlled. However, it is always anticipated for stable and controllable filamentation. We present and demonstrate the idea that hybridly polarized vector fields with axial symmetry broken polarization, associated with a pair of orthogonally linearly polarized vortices carrying the opposite-handed orbital angular momenta, could achieve controllable and robust multiple filamentation. Here, our motivation is to unveil the underlying physics behind such controllable and robust multiple filamentation. The symmetry breaking should first be actively controllable and then be able to effectively inhibit random noise. Robust multiple filamentation is inseparable from the fact that the phases between the multiple filaments are always locked. In contrast, uncontrollable multiple filamentation is always accompanied with loss of phase, i.e., the multiple filaments become incoherent to each other. Our results may offer a suggestion for achieving controllable and robust multiple filamentation in other systems.