Abstract
Free electron lasers have unique advantages; wide-range wavelength tunability, ultrashort pulse operation and intense peak power. The high-power coherent laser beam in the mid-infrared (MIR) region provides unique opportunities to investigate carrier dynamics in semiconductors. Band-gap luminescence from a variety of compound semiconductors has been observed with an intense MIR radiation beam being directed to the samples. The band-gap luminescence is attributed to impact-ionization following scattering-induced free-electron heating.
