单周期以上超短脉冲光束在自由空间中的矢量非傍轴传输方法

在Lax等建立的微扰法的基础上，应用傅里叶变换的方法得到了一种用于自由空间中单周期以上（即脉冲长度在一个振荡周期以上）脉冲光束的矢量非傍轴修正方法.在频域，其横向分量的一阶修正等价于Fu等所得相应结果，而在时域内则比Fu等所得结果更有利于非傍轴解析解的得出.通过量级关系证明了矢量效应在对标量傍轴光束修正中的必要性.从例子中发现，由于时空耦合的存在，超短脉冲光束中的矢量非傍轴效应会被其时间分布所影响.关键词：矢量非傍轴超短脉冲光束

The vectorial nonparaxial propagation method of the few-cycle ultrashort pulsed beam in free space

Based on the purterbative method which was developed by Lax et al, and by using of the Fourier transform, we obtain a vectorial nonparaxial correction method to the propagation of the few-cycle pulsed beam in free space. the first-order of the transverse component of the correction is the same as that of Fu's in the frequency domain, and is more convenient to obtain the analytical nonparaxial solution in the temporal domain. It is shown in the examples and the analysis that the vector corrections must be included in any study that wants to go beyond the scalar paraxial solution. From the examples, we find that the spatial distribution of the vectorial nonparaxial correction would be influenced by the temporal distribution of the pulse.