超相对论激光和稠密等离子体作用产生阿秒脉冲的优化

利用一维粒子模拟程序研究了超相对论激光脉冲与稠密等离子体相互作用得到的阿秒脉冲.从超相对论近似的角度分析了电子运动行为和高次谐波的产生,发现当等离子体密度一定时,随着无量纲相似参数S的减小,阿秒脉冲的转换效率呈先增大后减小的趋势,因此选择适当的光强就可以得到转换效率较高的阿秒脉冲.当S一定时,随着等离子体密度的增加,阿秒脉冲转换效率有增大的趋势.这说明用适当的光强照射更稠密度的等离子体靶面,可以产生更强的阿秒脉冲.

Optimization of attosecond pulses from the interaction of ultrarelativistic laser with overdense plasma

Using one-dimensional particle-in-cell simulations, the generation of attosecond pulses is studied due to the interaction of a short ultrarelativistic laser pulse with overdense plasma. According to the ultrarelativistic similarity theory, we analyze the motion of the electrons and the generation of high-order harmonics. We find that when the plasma density is constant and the dimensionless similarity parameter S decreases, the conversion efficiency of attosecond pulses first increases and then decreases. So we can choose a laser pulse with an appropriate intensity to obtain an attosecond pulse with a high conversion efficiency. Furthermore, when S is fixed, with the increase of the plasma density, the conversion efficiency of attosecond pulses shows an upward tendency. This implies that we can obtain a higher attosecond pulse when a laser with an appropriate intensity is incident on a denser plasma.