Speaker
Description
MeV ultrafast electron diffraction (UED) is a widely used tool for studying ultrafast structural dynamics in many scientific fields. The laser wakefield accelerator (LWFA), with its ultrahigh accelerating gradient, ultrasmall accelerating structure, and natural synchronization between the laser and the electron beam, offers new possibilities for building tabletop UED sources with high temporal resolution. Based on a 10-TW-class ultra-intense laser system, we carried out laser wakefield acceleration research and built a permanent-magnet-based compact high-quality beam transport system and a high-resolution diagnostic system based on terahertz (THz) deflecting cavity technology. Through beam transport and energy filtering, a diffraction probe with an energy spread of 3% and a charge of 11.9 fC was obtained. Characterized by the THz deflecting cavity, a temporal resolution of 49.8 fs was ultimately achieved. This study represents the first demonstration of a tabletop, hundred-femtosecond-level temporally resolved, MeV-level ultrafast electron diffraction facility based on a laser wakefield accelerator, demonstrating the broad application prospects of this novel scientific instrument in ultrafast dynamics research and marking another important breakthrough in the application of ultra-intense ultrafast lasers and laser wakefield accelerator technology in ultrafast science.