Abstract:

As one of the most important physical processes of strong-field laser-matter interaction, laser-driven electron-ion recollision is the fundamental process. As we have known, the well-known three-step model of HHG predicts that the cutoff law obeys Ecutoffþinspace}=þinspace}Ipþinspace}+þinspace}3.17Up, implying that the maximum kinetic energy of returning electron can be greatly extended by increasing the driving wavelength. With the long wavelength mid-infrared laser pulse, it is easy for the ponderomotive energy of the returning electron to be very large to excite the deep inner-shell electron, which may be used to investigate the ultrafast inner-shell electron dynamics.