Beyond carbon K-edge harmonic emission using spatially and temporally synthesized laser field

Summary form only given. We present numerical simulations of high-order harmonic generation (HHG) in helium atoms while subjects to a temporally synthesized and spatially non-homogeneous strong laser field. The goal is to demonstrate that such synthesis allows us to free new degrees of the HHG process in order to provide KeV photon energies. In this purpose many strategies, involving laser field tailoring for HHG, have been implemented. Approaches based on a combination of multiple colours or chirping techniques have been proposed to temporally synthesized the strong laser field within an optical cycle hence controlling the electronic wave packet trajectories at the origin of the HHG process. In addition others schemes have been established based on spatially synthesized a flat top lasers for the generation of HHG continuum and so isolated attosecond pulses.