Gaseous pre-lattice assisted supercontinuum enhancement of femtosecond laser filamentation

Abstract

White-light supercontinuum from a femtosecond laser filamentation is essential for many applications due to its broadening spectrum and remote sensing ability. We propose to enhance the supercontinuum intensity by presetting the gaseous lattice in the path of femtosecond laser filamentation. Our results show that the introduction of a gaseous lattice can increase the spectral intensity in both visible and infrared wings, up to about ten times over the no lattice case in a gas medium. We find that the gaseous lattice dramatically affects the time-domain evolutions of the optical intensity and the electron density during the nonlinear propagation of the pulse, thereby resulting in spectral intensity enhancement. The results provide a new way to enhance the supercontinuum generation in the ultra-intense nonlinear process by using a gaseous pre-lattice with a special spatial refractive index profile.