Mitryukovskiy Sergey, Liu Yi, Ding Pengji, Houard Aurélien, Couairon Arnaud, Mysyrowicz André
Laboratoire d'Optique Appliquée, ENSTA/CNRS/Ecole Polytechnique, 828, Boulevard des Maréchaux, Palaiseau F-91762, France.
Centre de Physique Théorique, Ecole Polytechnique, CNRS, Palaiseau F-91128, France.
Phys Rev Lett. 2015 Feb 13;114(6):063003. doi: 10.1103/PhysRevLett.114.063003.
Filaments produced in air by intense femtosecond laser pulses emit UV luminescence from excited N(2) and N(2)(+) molecules. We report on a strong dependence at high intensities (I≥1.4×10(14) W/cm(2)) of this luminescence with the polarization state of the incident laser pulses. We attribute this effect to the onset of new impact excitation channels from energetic electrons produced with circularly polarized laser pulses above a threshold laser intensity.
由高强度飞秒激光脉冲在空气中产生的细丝会从受激的N₂和N₂⁺分子发出紫外发光。我们报道了在高强度（I≥1.4×10¹⁴ W/cm²）下这种发光对入射激光脉冲偏振态的强烈依赖性。我们将这种效应归因于在高于阈值激光强度的圆偏振激光脉冲产生的高能电子引发的新的碰撞激发通道的出现。
