Tunable high-repetition-rate femtosecond few-hundred keV electron source

Abstract

Using three-dimensional particle-in-cell simulations, we demonstrate that femtosecond few-hundred keV electron pulses can be produced at a high repetition rate by tightly focusing few mJ few-cycle radially polarized laser pulses in a low density gas. In particular, we show that the laser pulse parameters and gas density can be optimized to cover the full 100?300 keV energy window that characterizes ultrafast electron diffraction imaging experiments. The active development of high-power laser sources promises routine operation at 1 kHz and above, allowing time-resolved electron diffraction on the femtosecond time scale.