面向高亮度超快电子束产生及传输的紫外超短激光脉冲三维整形研究

In the field of accelerator and ultrafast electron, three-dimensional shaping of radio-frequency (RF) photoinjector driving laser is significant to the generation and transmission of high brightness electron and the consequent performance improvement of these devices. Presently, although spatial light modulating, acousto-optic programmable dispersive filtering, and pulses stacking have already been applied in ultraviolet (UV) laser pulse shaping，it is still a challenge topic to generate a uniform cylindrical or uniform ellipsoidal driving laser pulse, which can compensate the nonlinear emittance of electron beam efficiently during generation or transmission. This project will systematically study uniform cylindrical UV pulse shaping by profile clipping and pulse stacking, and on this basis, study on three-dimensional quasiellipsoidal intensity distribution pulse shaping by profile clipping and spatial light modulating. Besides, time-resolved focusing based on pump-probe technology and Kerr effects will be studied to generate three-dimensional quasiellipsoidal spatial distribution on the target surface. Finally, we try to obtain three-dimensional uniform quasiellipsoidal UV laser pulses and theoretically & experimentally promote the research in this field.

在加速器/超快电子领域，射频光阴极电子枪驱动激光的三维整形对高亮度电子束产生、传输并最终提升这类装置的性能具有重要意义。目前，空间光调制、声光可编程色散滤波、脉冲堆叠等时域整形方法已经广泛应用到紫外激光整形中，但可有效补偿电子束产生和传输过程中非线性发射度的均匀圆柱或均匀椭球分布整形仍是极具挑战的课题。本项目将在理论上和实验上系统研究横剖面剪切与脉冲堆叠产生均匀圆柱分布紫外超短脉冲的技术；在此基础上进一步将横剖面剪切技术与空间光调制技术结合起来，开展三维准椭球强度分布整形研究；此外，本项目也将利用基于泵浦-探测技术和光Kerr非线性效应的时间分辨聚焦方法开展三维准椭球空间分布整形，最终尝试获得均匀准椭球分布的紫外超短脉冲，从理论和实验上推进该方向的研究。

在加速器/超快电子探测领域，射频光阴极电子枪驱动激光的三维整形，特别是有效补偿电子束非线性发射度的均匀圆柱或均匀椭球分布整形研究对高亮度电子束产生、传输并最终提升装置性能具有重要意义。本项目在理论上和实验上研究了横剖面剪切与脉冲堆叠产生均匀圆柱分布紫外超短脉冲的技术，发展了完备的计算程序，在实验上实现了均匀平顶、“凹”型、均匀脉冲串等分布并应用到超快电子成像、库伦力压缩电子束、激光-微波相位抖动测量等实验中。此外，本项目基于泵浦-探测技术和光Kerr非线性效应的时间分辨聚焦方法开展了三维均匀准椭球分布整形的理论研究，从理论上分别为UV激光脉冲和泵浦激光脉冲计算了振幅调制曲线和相位调制曲线。基于本项目的理论计算结果，实验研究三维均匀准椭球紫外脉冲将是我们未来的重点。