Ultrafast dynamics of three types of simultaneous shockwaves and filament attenuation in femtosecond laser multi-pulse ablation of PMMA
Cylindrical shockwave inside PMMA generated simultaneously with two hemispherical shockwaves induced by femtosecond Gaussian beam laser was investigated using ultrafast pump-probe imaging technique. The evolutions of these three shockwaves with probe delay and incident pulse number have been systematically analyzed. The plasma intensity and filament length in the center of cylindrical shockwave both decayed with pulse number. Moreover, the self-focused filament moved downstream towards the output surface with increased pulse number. The experimental results and mechanism illustrated that energy deposition was suppressed by degraded nonlinear effect due to pre-ablated structure in multi-pulses irradiation.
作者单位：Beijing Insitute of Technology
Wang Guoyan,Jiang Lan,Sun Jingya,Hu Jie,Wang Qingsong,Li Ming,Lu Yongfeng. Ultrafast dynamics of three types of simultaneous shockwaves and filament attenuation in femtosecond laser multi-pulse ablation of PMMA[J].Chinese Optics Letters,2019,17(8):08.