title: Influence of the external focusing and the pulse parameters on the propagation of femtosecond annular Gaussian filaments in air.
abstract: We numerically investigate the effects of the external focusing and the pulse parameters on the propagation of the ring Gaussian filaments in air. The simulation results indicate that the onset distance of filament, the length and uniformity of the plasma strings, and the energy deposition strongly depend on these optical parameters. The length of optical filament can be extended greatly by adjusting the lens parameters near the maximum energy deposition. In addition, we find that, under the same initial intensity, the length and uniformity of the plasma strings can be tuned by increasing the beam width better than increasing the beam radius.
authors.forename: ZhiFang
authors.initials: Z
authors.lastname: Feng
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: ChengXin
authors.initials: C
authors.lastname: Yu
authors.forename: Xun
authors.initials: X
authors.lastname: Liu
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.forename: LiBin
authors.initials: L
authors.lastname: Fu