ULTRAFAST DETECTION AND AUTOCORRELATION OF PICOSECOND THZ RADIATION PULSES WITH A GAAS ALAS SUPERLATTICE/

We used a wide miniband GaAs/AlAs superlattice (at room temperature) f or detection and autocorrelation of picosecond THz radiation pulses (f requency 4.3 THz) from a free- electron laser. The detection was based on a THz-field induced change in conductivity of the superlattice, an d the correlation on the nonlinearity of the conductivity change at st rong THz-pulse- power. The nonlinear conductivity change was due to tw o effects, which we attribute to dynamical localization of miniband el ectrons and to ionization of deep impurity centers. (C) 1998 American Institute of Physics. [S0003-6951(98)04946-8].