Time-Resolved Pump and Probe Experiment for Wide-Gap Semiconductors Using Free Electron Laser and Synchronously-Operated Femtosecond Laser

Pump-probe technique is an important means of studying the structure and dynamics of a single protein molecule. X-ray free electron lasers (XFELs) such as the Linac Coherent Light Source (LCLS) and SPring-8 Angstrom Compact free electron Laser (SACLA) provide the Angstrom-wavelength, high-intensity femtosecond pulses needed for revealing the structure of a single protein molecule without crystallization and for observing atomic motion during a chemical reaction via pump-probe experiments. In this paper, we demonstrated X-ray pump-optical probe and optical pump-X-ray probe experiments, creating new possibilities for time-resolved EUV spectroscopy of solid targets including wide-gap semiconductors such as gallium nitride. (C) 2013 The Japan Society of Applied Physics