Photon acceleration versus frequency-domain interferometry for laser wakefield diagnostics

Abstract

A detailed comparison between photon acceleration and frequency-domain interferometry, for laser wakefield diagnostics, is presented here. The dispersion effects on the probe beam and the implications of an arbitrary phase velocity of the plasma wave are discussed for both diagnostic techniques. In the presence of a large amplitude plasma wave and for long interaction distances, significant frequency up-shifts are observed. The importance of this effect on the determination of the phase and frequency shift measurements given by the two techniques is also analyzed. The accuracy of both diagnostics is discussed and some of their technical problems are reviewed.