Laser-induced melting of a single crystal gold sample by time-resolved ultrafast relativistic electron diffraction

We report the experimental demonstration of time-resolved relativistic electron diffraction. Single shot diffraction patterns from a single crystal gold sample were recorded using ultrashort 3.5 MeV electron bunches from a radio frequency photoinjector. By scanning the pump pulse time-delay, we studied the Bragg peaks amplitude change due to the laser-induced melting of the sample. The observed time scale matches the one predicted using a simple two temperature model of the heating of the thin foil. Time-resolved relativistic electron diffraction using megaelectronvolt electron beams with 107 particles in 100 fs bunch length opens exciting possibilities in ultrafast structural dynamics.