Single-shot spatiotemporal measurements of high-field terahertz pulses

The electric field profiles of broad-bandwidth coherent terahertz (THz) pulses, emitted by laser-wakefieldaccelerated electron bunches, are studied. The near- single-cycle THz pulses are measured with two singleshot techniques in the temporal and spatial domains. Spectra of 0-6 THz and peak fields up to similar or equal to 0.4 W cm(-1) are observed. The measured field substructure demonstrates the manifestation of spatiotemporal coupling at focus, which affects the interpretation of THz radiation as a bunch diagnostic and in highfield pump-probe experiments. (c) 2007 Optical Society of America.