Coherent THz plasmons in GaAs/AlGaAs super lattices

摘要

We report on THz emission from coherent plasma oscillations in GaAs/AlGaAs superlattices after excitation by femtosecond laser pulses. The carriers which oscillate inside the superlattice are either dopant electrons or electrons that are optically generated by the laser pulses. The oscillations are observable from low temperatures up to room temperature. A nearly full or a full miniband prevents these oscillations as it is the case when the miniband is thermally saturated.