Differential electronic gating: A method to measure the shape of short THzpulses with a poorly defined trigger signal

A simple experimental method has been developed to determine the shape of r epetitive picosecond THz pulses in the presence of a large jitter in the tr igger signal. This method, a modification of the recently reported differen tial optical gating method, is based on the femtosecond electronic gating o f a high-frequency sequential oscilloscope. As a test, the shape of THz pul ses from the free-electron laser has been measured. (C) 2000 American Insti tute of Physics. [S0003-6951(00)03738-4].