The generation and control of serpentine femtosecond laser filament array

Abstract

Some potential applications require controllable curved femtosecond laser filaments. We show how a gas lattice medium with periodic refractive index profiles can generate a serpentine filament array of a femtosecond laser Gaussian pulse. The simulation findings show that the curved characteristics (bending times and degree), spatial evolution (onset, termination and interval) and energy fluence profiles of the filaments, can be flexibly controlled by adjusting the various parameters of the gas lattice. When collapsing Gaussian laser pulse is coupled into the asymmetric gas lattice, the optical waveguide effect in a medium with a refractive index gradient plays a vital role in forming the continuously curved trajectory. By adjusting the gas lattice parameters, serpentine filaments with customised characteristics can also be obtained. Our research provides a new method for manipulating the strong nonlinear propagation trajectories, which is for the first time to tailor serpentine filaments by utilising a modulated dielectric medium and offers a unique solution for many potential applications.