LIMITATIONS OF ELECTRO-OPTIC MEASUREMENTS OF ELECTRON BUNCH LONGITUDINAL PROFILE

We provide quantitative comparisons of the fundamental limits of the principal techniques for electro-optic longitudinal profile measurements. The comparisons are based on simulations using the Coulomb field/optical field frequency mixing description of the electro-optic effect, with both time domain and spectral domain measurements considered. The important distinction between “temporal resolution” and “temporal limitation” which is encountered in the spectral measurements is highlighted by example. Effects of phase matching (or velocity mismatch of fields) in the detection crystal, the non-linear coefficient frequency response, and the choice of “balanced” or “crossed-polariser” detection are also considered.