Center for Ultrafast Optical Science, University of Michigan, 2200 Bonisteel, Ann Arbor, Michigan 48109, USA.
Phys Rev Lett. 2009 Dec 4;103(23):235001. doi: 10.1103/PhysRevLett.103.235001. Epub 2009 Dec 1.
We investigate the production of electron beams from the interaction of relativistically-intense laser pulses with a solid-density SiO(2) target in a regime where the laser pulse energy is approximately mJ and the repetition rate approximately kHz. The electron beam spatial distribution and spectrum were investigated as a function of the plasma scale length, which was varied by deliberately introducing a moderate-intensity prepulse. At the optimum scale length of lambda/2, the electrons are emitted in a collimated beam having a quasimonoenergetic distribution that peaked at approximately 0.8 MeV. A highly reproducible structure in the spatial distribution exhibits an evacuation of electrons along the laser specular direction and suggests that the electron beam duration is comparable to that of the laser pulse. Particle-in-cell simulations which are in good agreement with the experimental results offer insights on the acceleration mechanism by the laser field.
我们研究了在激光脉冲能量约为毫焦且重复率约为千赫兹的条件下，相对论强度激光脉冲与固体密度 SiO(2) 靶相互作用产生电子束的情况。我们研究了电子束空间分布和谱作为等离子体尺度长度的函数，通过故意引入中等强度的预脉冲来改变等离子体尺度长度。在最佳的 lambda/2 尺度长度下，电子以准单能分布发射，峰值约为 0.8 MeV。空间分布中高度重现的结构表现出沿着激光反射方向的电子排空现象，并表明电子束持续时间与激光脉冲相当。与实验结果非常吻合的粒子模拟为激光场的加速机制提供了深入的见解。
