Ultrafast electrooptic effect: from photorefractive Gunn domain to terahertz frequency space charge waves

摘要

We demonstrate an ultrafast electrooptic effect in highly photoexcited photorefractive semiconductors due to hot carrier nonlinear transport in high frequency electric fields, ranging from 50 GHz to 1 THz. Numerical analysis, taking into account nonuniform electron gas heating, intervalley scattering, and field shielding has been performed at various nonequilibrium carrier densities, field frequencies and amplitudes. Conditions for efficient space charge wave formation, which exceeds the diffusive field amplitude by 100 times and follows the external THz frequency microwave field have been established.