Beyond Carbon K-edge harmonic emission using spatial and temporal synthesized laser field

We present numerical simulations of high-order harmonic generation in helium using a temporally synthesised and spatially non-homogeneous strong laser field. The combination of temporal and spatial laser field synthesis results in a dramatic cut-off extension far beyond the usual semiclassical limit. Our predictions are based on the convergence of three complementary approaches: resolution of the three dimensional Time Dependent Schrödinger Equation, time-frequency analysis of the resulting dipole moment and classical trajectories extraction. Employing a combination of temporally and spatially synthesised laser field provides coherent XUV photons beyond the carbon K-edge which is of high interest for initiating inner-shell dynamics and study time-resolved intra-molecular attosecond spectroscopy.