Abstract

Recently, terahertz electromagnetic-pulse radiation has been generated from semiconductor surfaces' and quantum-well structures^2,3 by using an intensive laser pulse. It has been shown that a nonlinear optical rectification theory⁴ can explain all the major observed phenomena of the electromagnetic-pulse generation in the femtosecond regime. The crystal-orientation dependence, i.e., the variation of the terahertz signal with the azimuthal angle with the angle of incidence fixed, has provided the strongest evidence⁴ for the validity of optical-rectification theory as opposed to the current-surge model.

© 1993 Optical Society of America