  We have made the first observation of a charged particle beam by means of its
electro-optical effect on the polarization of laser light in a birefringent
crystal. The modulation of the laser light during the passage of a pulsed
electron beam was observed using a fast photodiode and a digital oscilloscope.
The fastest rise time measured in a single shot, 120 ps, was limited by the
bandwidth of the oscilloscope and the associated electronics. This technology
holds promise for detectors of greatly improved spatial and temporal resolution
for single relativistic charged particles as well as particle beams.
