Electron bunch length measurements from laser-accelerated electrons using single-shot thz time-domain interferometry

Debus, A.D. and Bussmann, M. and Schramm, U. and Sauerbrey, R. and Murphy, C.D. and Major, Z. and Hörlein, R. and Veisz, L. and Schmid, K. and Schreiber, J. and Witte, K. and Jamison, S.P. and Gallacher, J.G. and Jaroszynski, D.A. and Kaluza, M.C. and Hidding, B. and Kiselev, S. and Heathcote, R. and Foster, P.S. and Neely, D. and Divall, E.J. and Hooker, C.J. and Smith, J.M. and Ertel, K. and Langley, A.J. and Norreys, P. and Collier, J.L. and Karsch, S. (2010) Electron bunch length measurements from laser-accelerated electrons using single-shot thz time-domain interferometry. Physical review letters, 104 (8). ISSN 1079-7114

Abstract

Laser-plasma wakefield-based electron accelerators are expected to deliver ultrashort electron bunches with unprecedented peak currents. However, their actual pulse duration has never been directly measured in a single-shot experiment. We present measurements of the ultrashort duration of such electron bunches by means of THz time-domain interferometry. With data obtained using a 0.5 J, 45 fs, 800 nm laser and a ZnTe-based electro-optical setup, we demonstrate the duration of laser-accelerated, quasimonoenergetic electron bunches [best fit of 32 fs (FWHM) with a 90% upper confidence level of 38 fs] to be shorter than the drive laser pulse, but similar to the plasma period.