Realizing Ultrafast Electron Pulse Self-Compression by Femtosecond Pulse Shaping Technique

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• 作者：Yingpeng Qi ; Minjie Pei ; Dalong Qi ; Yan Yang ; Tianqing Jia ; Shian Zhang ; Zhenrong Sun
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2015
• 出版时间：October 1, 2015
• 年：2015
• 卷：6
• 期：19
• 页码：3867-3872
• 全文大小：312K
• ISSN：1948-7185

文摘

Uncorrelated position and velocity distribution of the electron bunch at the photocathode from the residual energy greatly limit the transverse coherent length and the recompression ability. Here we first propose a femtosecond pulse-shaping method to realize the electron pulse self-compression in ultrafast electron diffraction system based on a point-to-point space-charge model. The positively chirped femtosecond laser pulse can correspondingly create the positively chirped electron bunch at the photocathode (such as metal鈥搃nsulator heterojunction), and such a shaped electron pulse can realize the self-compression in the subsequent propagation process. The greatest advantage for our proposed scheme is that no additional components are introduced into the ultrafast electron diffraction system, which therefore does not affect the electron bunch shape. More importantly, this scheme can break the limitation that the electron pulse via postphotocathode static compression schemes is not shorter than the excitation laser pulse due to the uncorrelated position and velocity distribution of the initial electron bunch.