相対論的超短電子パルスによる超高速固体構造動力学の研究

摘要

We develop a compact ultrafast electron diffractometer, consisting of a laser-driven rf photocathode that generates 3.0 MeV probe electron pulses with 100-fs temporal widths. High-quality single-shot transmission electron diffraction is detected under kinematic regimes using three-stage lens optics and a high-sensitive detector. Combining theoretical modelling with single-shot diffraction measurements, we are now capable of characterizing the dynamics of atomic structures underpinning the temporal evolution of the Bragg peaks. The feasibility of the approach is demonstrated on the example of photo-induced melting of 10-nm thick gold films. Our results show that dynamic structure determination in laser-excited systems is now a viable prospect using ultrafast electron diffraction.