High‐power switching with picosecond precision

Up to 10 kV have been switched with Si and GaAs laser‐activated switches. We show that in spite of the thermal instability shortcoming experienced in Si, quasi‐dc bias operation can be utilized in a manner which relaxes stringent synchronization requirements. In the case of GaAs the thermal instability is less severe and up to 8 kV dc has been held off and efficiently switched. In both cases, a fast switching time of ∼40 ps is observed. This time is a combination of the laser pulse width, geometry bandwidth, and jitter time. Efficient switching action requires only a few tens of microjoules of laser energy. Electrical pulses ranging from subnanosecond to hundreds of nanoseconds duration have been readily generated.