阿秒脉冲测量的研究进展

Evolution of attosecond pulse measurement

对于发生在原子范围内的电子动力学过程的观测需要阿秒量级的时间分辨率.理论和实验研究都已证明,用周期量级超短脉冲直接泵浦的高次谐波过程可以产生阿秒脉冲序列甚至单个的阿秒脉冲,将阿秒脉冲用于测量超快动力学过程之前先要对阿秒脉冲本身性质做出描述,传统的自相关方法和互相关方法不能直接推广到阿秒量级超短脉冲的测量.文章详细介绍了近几年发展起来的阿秒脉冲测量方法,分析了它们的分辨极限和局限性.

Observation of the dynamic behavior of electrons in atoms requires attosecond time resolution measurement. Theoretical study and experimental results have shown that an attosecond pulse train and even a single attosecond pulse can be produced by high-order harmonic generation with a few-cycle ultrashort laser pulse. Before attosecond pulses can be used to characterize the dynamic behavior of matter with ever-shorter ti-mescales, an unequivocal method to characterize the pulse itself must be employed. The conventional autocorrelation and cross correlation technique cannot be extended to the measurement of attosecond pulses directly. Various techniques developed recently for the measurement of attosecond pulses are introduced in detail, and their resolution and limitations analyzed.