Air filamentation characteristics of ring Airy femtosecond laser beam with different background energies

Filamentation has stimulated growing research interest since the first observation of filament generated by an intense femtosecond laser pulse in air. Possible applications of filaments have also been proposed and demonstrated in laser induced electrical discharge particle acceleration, lidar remote sensing, THz radiation generation, and pulse compression. The characteristics of filamentation with a modulation of background energy distribution was presented by changing the confinement parameter of ring Airy beam numerically. The length of filaments longer than that of the Gaussian beam with faint background energy of the same peak power was achieved. By analyzing the spatial and temporal evolution progresses, it was found that the Airy beam airy-function-like energy distribution along radius of the background energy was the prerequisite to achieve peak intensity along the propagation direction. With comparison of spectra evolution consequences, it was found that the changing of the confinement parameter of Airy beam doesn't have significant influence on the spectral broadening. But when changing the beam from ring Airy to Gaussian, the spectra is broadened dramatically.