Regulating the higher harmonic cutoffs via sinc pulse

Abstract

We theoretically investigate the generation of higher harmonics and the construction of a single attosecond pulse by means of two oppositely polarized sinc-shaped driver pulses. In comparison to a few-cycle Gaussian pulse of the same energy, here we observe a significant broadening in the bandwidth of an XUV/soft-Xray supercontinuum spectrum in the synthesized pulse. Furthermore, we observe that the harmonic cutoff and its corresponding intensity follow a well-defined scaling with the {\it delay parameter} between the two pulses. In principle, this delay can easily be tuned in on an optical bench. The typical nature of the synthesized pulse ensures the generation of single attosecond pulse instead of a pulse train. In this case, we obtain a single attosecond pulse of duration $\sim 27$ as in XUV/soft-Xray regime of the electromagnetic spectrum. Depending on the delay parameter we observe an enhancement in some satellite harmonics. The proposed setup promises a highly tunable source of energetic photons, wherein the energy of the photons can easily be controlled from XUV to soft-Xray regime by simply changing the delay between two oppositely polarized sinc-pulses.