Ultrashort high energy electron bunches from tunable surface plasma waves driven with laser wavefront rotation

We propose to use ultrahigh intensity laser pulses with wave-front rotation (WFR) to produce short, ultraintense surface plasma waves (SPW) on grating targets for electron acceleration. Combining a smart grating design with optimal WFR conditions identified through simple analytical modeling and particle-in-cell simulation allows us to decrease the SPW duration (down to a few optical cycles) and increase its peak amplitude. In the relativistic regime, for I?02=3.4×1019W/cm2?m2, such SPW are found to accelerate high charge (few 10 s of pC), high energy (up to 70 MeV), and ultrashort (few fs) electron bunches.