A relativistic linearly polarized Laguerre–Gaussian (LG) laser pulse interacting with a combination of gas plasma and an oblique foil target is proposed to generate an intense attosecond pulse carrying large orbital angular momentum (OAM). The LG laser pulse firstly produces an ultra-thin relativistic electron sheet (RES) in underdense plasma and transfers the OAM to the latter at the same time. When the RES passes through the oblique foil, it radiates an intense half-cycle attosecond pulse carrying large OAM. Three-dimensional particle-in-cell simulation confirms that an isolated ultra-intense half-cycle attosecond pulse with a duration of 542 as and a peak electric field of 5 10¹² V m⁻¹ is produced. The average OAM per photon of the attosecond pulse is about −1ћ. Such an intense, isolated attosecond pulse with the large OAM would provide new possibilities in attosecond scientific research.

提出了一种与气体等离子体和斜箔靶结合的相对论性线性偏振拉盖尔-高斯（LG）激光脉冲，以产生携带大轨道角动量（OAM）的强阿秒脉冲。LG激光脉冲首先在低密度等离子体中产生超薄相对论电子片（RES），然后将OAM转移到后者。当RES通过斜箔时，它会辐射出一个带有大OAM的强烈的半周期阿秒脉冲。三维单元粒子仿真证实，产生了一个持续时间为542 as且峰值电场为5 10 ¹² V m ^-1的孤立的超强半周期阿秒脉冲。阿秒脉冲的每个光子的平均OAM约为-1ћ。如此大的OAM如此强烈的孤立阿秒脉冲将为阿秒科学研究提供新的可能性。