Point Guillaume, Liu Yi, Brelet Yohann, Mitryukovskiy Sergey, Ding Pengji, Houard Aurélien, Mysyrowicz André
Opt Lett. 2014 Apr 1;39(7):1725-8. doi: 10.1364/OL.39.001725.
We report on the lasing action of atmospheric air pumped by an 800 nm femtosecond laser pulse with peak power up to 4 TW. Lasing emission at 428 nm increases rapidly over a small range of pump laser power, followed by saturation above ∼1.5 TW. The maximum lasing pulse energy is measured at 2.6 μJ corresponding to an emission power in the MW range, while a maximum conversion efficiency of 3.5×10(-5) is measured at moderate pump pulse energy. The optical gain inside the filament plasma is estimated to be in excess of 0.7/cm. Lasing emission shows a doughnut profile, reflecting the spatial distribution of the pump-generated white-light continuum that acts as a seed for the lasing. We attribute the pronounced saturation to the defocusing of the seed in the plasma amplifying region and to the saturation of the seed intensity.
我们报道了由峰值功率高达4太瓦的800纳米飞秒激光脉冲泵浦的大气空气的激光作用。在428纳米处的激光发射在泵浦激光功率的小范围内迅速增加，然后在约1.5太瓦以上达到饱和。测量到的最大激光脉冲能量为2.6微焦，对应兆瓦范围内的发射功率，而在中等泵浦脉冲能量下测量到的最大转换效率为3.5×10^(-5)。丝状等离子体内的光学增益估计超过0.7/厘米。激光发射呈现出环形分布，反映了作为激光种子的泵浦产生的白光连续体的空间分布。我们将明显的饱和归因于种子在等离子体放大区域的散焦以及种子强度的饱和。
