Temporal control of high-order harmonic cutoffs in periodic crystals

A theoretical study on the high-order harmonic generation (HHG) in solids by a synthesized driver field is carried out. The vector potential of the driver field is instrumental in determining the Bloch oscillations of the electrons in a periodic crystal, which eventually reflects in the high-order harmonic spectra. To this end, the interaction of the sinc-shaped driver with periodic crystal is studied. It is observed that the emission time of the harmonic cutoff can be controlled by varying the delay parameter introduced in the proposed sinc-shaped driver with a well-defined scaling that depends on the energy bands of the periodic crystal under study. Furthermore, it is also observed that the emission time of the cutoff harmonics and even the harmonic cutoff energy can also be controlled by varying the delay parameter systematically. An optimum delay parameter for maximum harmonic cutoff energy and harmonic yield is also deduced. From the applied perspective, the temporal control of the cutoff harmonics is also demonstrated by the superposition of the subcycle pulsed vector beam.