Picosecond pulse frequency upshifting by rapid free-carrier creation in ZnSe

The frequency upshifting of 0.8 mum picosecond laser pulses was demonstrated using the temporal change of the free carrier density in a ZnSe semiconductor crystal. The crystal was ionized by transverse propagating ps pulses. Shifts of up to 1.6 nm were observed, which agree within 25% with the theory. (C) 2002 American Institute of Physics.