用拉盖尔-高斯激光对真空中电子直接加速

Direct acceleration of electrons by a Laguerre-Gaussian laser beam in vacuum

对用拉盖尔-高斯(LG)光束加速电子作了研究.结果表明,仅模指数为p和l=1的LG光束的纵向电场可用于加速电子.模指数为p和l=1的线偏振和圆偏振LG光束都对电子有加速效果.对轴上光场的相速度和群速度以及电子能量增益等物理特征作了讨论.给出了轴上光场的相速度和群速度、加速电位及电子能量增益等的解析表达式,并作了数值计算和分析.

The acceleration of electrons by a Laguerre-Gaussian（LG） beam in vacuum is studied. It is shown that only the longitudinal electric field of the LG beam with mode indices p and l = 1 can be used to accelerate electrons. The linearly- and circularlypolarized LG beams with mode indices p and l = 1 effectively play the role in laser electron acceleration. Some physical characteristics, such as phase and group velocities of the axial optical field, and energy gain of electrons etc., are discussed. The analytical expressions for the phase and group velocities of the axial optical field, accelerating potential and energy gain etc. are derived and are used to make numerical analysis.