Abstract

GaAs pulse-power switches have displayed unexpected, complex behavior under the 1-50-kV/cm bias fields typical of high-voltage operation. Above a certain threshold field of 3–8 kV/cm, depending on material preparation GaAs switches have been observed to remain conductive a long time (hundreds of nanoseconds) after the optical excitation, inconsistent with the normal carrier recombination time of ~1 ns. This unexplained phenomenon was first reported by Loubriel et al,^1,2 and has been given the name lock-on as the switch is said to lock-on to the conducting state. In experiments performed at the Laboratory for Laser Energetics, an ultrafast EO imaging system was used to investigate the dynamic behavior of the electric field in high-power GaAs switches during operation to provide some insight into the physical basis of lock-on.

© 1992 Optical Society of America