自从第一次观察到飞秒激光大气成丝后, 光丝备受科学家的关注。它的潜在应用价值主要包括电子加速、激光雷达远程遥感、太赫兹辐射和超短脉冲压缩。利用数值仿真的方法, 通过改变艾里光束的衰减系数, 研究了不同能量背景的环形艾里光束飞秒激光大气成丝特性, 得到的光丝长度长于拥有相同峰值功率、弱能量背景高斯光束形成的光丝。通过分析飞秒激光光丝演化过程的时间和空间特性, 发现了环形能量背景是环形艾里光束沿传播方向形成高能量密度光丝的前提条件。比较了环形艾里光束和高丝光束在成丝过程中的光谱展宽特性, 发现不同衰减系数的环形艾里光束具有相似的光谱展宽特性, 但要明显弱于高斯光束的光谱展宽。研究成果对与提升飞秒激光成丝效果具有参考意义。

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.