We present the experimental optimization of electrons in the several hundred keV energy range originated from laser-irradiated wire targets. Accelerated by a femtosecond laser pulse, an electron pulse emitted from the wire target was collimated immediately along the wire to a filter unit for the manipulation of energy and spatial distributions. It is shown in simulation that with a pair of magnets as the filter unit, the optimized electrons could serve as a compact and tunable electron source. The proposed system was demonstrated in a proof-of-principle experiment where we attained 1 fC bunch charge with transverse coherence length approaching 1 nm based on a 0.2 TW laser platform. This indicates the scheme as a promising candidate for single-shot electron diffraction.

我们介绍了在数百keV能量范围内电子的实验优化，这些能量源自激光辐照的导线靶材。从飞秒激光脉冲加速，从焊丝靶发射的电子脉冲立即沿焊丝准直，到达用于控制能量和空间分布的过滤器单元。在仿真中显示，使用一对磁体作为滤波单元，优化后的电子可以用作紧凑且可调的电子源。在原理证明实验中证明了所提出的系统，其中基于0.2 TW激光平台，我们获得了1 fC束电荷，其横向相干长度接近1 nm。这表明该方案是单次电子衍射的有希望的候选方案。