A technique of Optical Sampling relying on photoconductive switches.

On such a switch, a short Laser pulse can close an electrical connection for a very short time. A second photoconductive Switch (obtaining a delayed portion of the laser pulse) may be used for sampling of the resulting signal at a different location: the switch connects the corresponding part of the circuit with some output lead only for a very short time interval, the temporal position of which can be adjusted via an optical delay line.