Manipulation of femtosecond laser filamentation by a gaseous lattice

Manipulation of femtosecond laser filamentation is essential for many potential applications. We report the simulations of the manipulation of femtosecond laser filamentation by introducing a novel gaseous lattice medium with the alternating positive and negative refractive index distribution at different stages of filamentation. The results show that the filament length has greatly been extended and a multi-filament array can be formed by the gas lattice medium. It has been found that additional focusing and discrete diffraction provided by the gas lattice medium contribute to a new dynamic equilibrium in the filamentation. As a result, a varied cross-section pattern, higher field intensity, and electron density along the filamentation are obtained. Our approach provides a new way to manipulate filamentation for many practical photonic applications.