Kerrigan Haley, Masnavi Majid, Bernath Robert, Fairchild Shermineh Rostami, Richardson Martin
Opt Express. 2021 Jun 7;29(12):18481-18494. doi: 10.1364/OE.420599.
The laser-plasma interactions that occur during the ablation of solid materials by a femtosecond filament superimposed with a lower-intensity nanosecond pulse are investigated. Pulses of 50 fs duration with intensities of ∼10 W/cm centered at 800 nm are combined with 8 ns pulses at 1064 nm with ∼10 W/cm intensity with delays of ±40 ns on crystalline GaAs targets in air. For each delay, the volume of material removed by a single femtosecond-nanosecond dual-pulse is compared to the laser-plasma interactions that are captured with ultrafast shadowgraph imaging of the plasma and shockwave generated by each pulse. Sedov-Taylor analysis of the shockwaves provides insight on the coupling of energy from the second pulse to the plasma. These dynamics are corroborated with radiation-hydrodynamics simulations. The interaction of the secondary pulse with the pre-existent plasma is shown to play a critical role in enhancing the material removal.
研究了飞秒细丝与低强度纳秒脉冲叠加在固体材料烧蚀过程中发生的激光-等离子体相互作用。在空气中的晶体砷化镓靶上，将持续时间为50 fs、强度约为10 W/cm²、中心波长为800 nm的脉冲与波长为1064 nm、强度约为10 W/cm²、延迟为±40 ns的8 ns脉冲相结合。对于每个延迟，将单个飞秒-纳秒双脉冲去除的材料体积与通过对每个脉冲产生的等离子体和冲击波进行超快阴影成像所捕获的激光-等离子体相互作用进行比较。对冲击波的塞多夫-泰勒分析提供了关于能量从第二个脉冲耦合到等离子体的见解。这些动力学通过辐射流体动力学模拟得到了证实。结果表明，二次脉冲与预先存在的等离子体的相互作用在增强材料去除方面起着关键作用。
