Filament-necklace generated by femtosecond vector beams in fused silica

The realization of organized filaments in transparent media is a great challenge in the filamentation field, which generally needs complicated design on the light field, and it is also difficult to control the filament arrays rotating and determine the filaments number at the same time. In this work, we propose a convenient method to generate regularly distributed multiple filaments of femtosecond vector laser beams in fused silica by simply filtering the polarization of the vector beams with a polarizer. The filaments are found to be evenly distributed in the ring of the vector beam, forming a filament-necklace which remains stable along the propagation direction. The filaments number is determined by the topological charges of the vector beams. Furthermore, the pattern of filament-necklace can be continuously rotated by rotating the polarizer. This method provides a simple and effective way to generate stable filament-necklace in transparent media and to rotate the pattern to any angle through exterior regulation. •A simple method to generate regular distributed filaments of femtosecond vector laser beams in fused silica.•The filaments number is determined by the topological charges of the laser beams.•The necklace-like distribution of filaments can be continuously rotated by simply rotating the polarizer.•This method to produce controllable femtosecond filaments can also be applied to other kinds of vector beams.