Simulation of cross-correlation method for temporal characterization of VUV free-electron-lasers

• 来源期刊: 中国光学快报（英文版）
• 年，卷（期）: 2013,（9）
• 页码范围: 55-59
• 页数: 5页
• 语种: 英文
• DOI: 10.3788/COL201311.091403

摘要

The cross-correlation method for temporal characterization is investigated using simulations of the twocolor above threshold ionization (ATI) on He induced by a vacuum ultraviolet (VUV) free-electron laser (FEL) in the presence of an infrared (IR) field.Non-linear dependencies of the sideband structure produced in the two-color ATI process are expressed as a function of IR laser intensity by considering the spatial distributions and temporal jitter of both lasers.The temporal properties of the FEL pulse can be characterized accurately using the cross-correlation method at a low IR laser intensity of ～3×1010W/cm2 but with low cross-correlation signals.When the dynamic range of sidebands is increased to high IR intensity,the accuracy of the cross-correlation method becomes crucially dependent on the actual nonlinear index.An approach of determining this index is proposed here to improve the accuracy of temporal characterizations.