Electro-optic detection of the Coulomb field of a relativistic electron bunch combined with single-shot cross correlation of optical pulses is used to enable single-shot measurements of the shape and length of femtosecond electron bunches. This method overcomes a fundamental time-resolution limit of previous single-shot electro-optic measurements, which arises from the inseparability of time and frequency properties of the probing optical pulse. Using this new technique we have made real-time measurements of a 50 MeV electron bunch, observing the profile of 650 fs FWHM (∼275 fs rms) long bunches.
Berden, G., Jamison, S. P., MacLeod, A. M., Gillespie, W. A., Redlich, B., & van der Meer, A. F. G. (2004). Electro-optic technique with improved time resolution for real-time, nondestructive, single-shot measurements of femtosecond electron bunch profiles. Physical Review Letters, 93(11), [ 114802]. https://doi.org/10.1103/PhysRevLett.93.114802