Femtosecond electron diffraction for direct measurement of ultrafast atomic motions

We have developed a femtosecond electron diffraction system capable of directly measuring the complete transient structures with atomic level detail and on 400-fs time scale in solid materials. Additionally, a diffraction image with significant signal-to-noise ratio to reveal the long-range order can be obtained with a single electron pulse of 700 fs in duration. A direct observation of ultrafast lattice expansion following the irradiation of femtosecond pulsed laser of Ag film has been demonstrated. (C) 2003 American Institute of Physics.