We theoretically investigate the generation of higher harmonics and the construction of a single attosecond pulse (ASP) 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 the XUV/soft x-ray supercontinuum spectrum in the synthesized pulse. Furthermore, we observe that the harmonic cutoff and its corresponding intensity follow a well-defined scaling with the delay parameter between the two pulses. In principle, this delay can easily be tuned on an optical bench. The typical nature of the synthesized pulse ensures the generation of a single ASP instead of a pulse train. In this case, we obtain a single ASP with a duration of ∼27 attoseconds in the XUV/soft x-ray 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 the XUV to the soft x-ray regime by simply changing the delay between two oppositely polarized sinc-pulses

Abstract

We study operator entanglement of the quantum chaotic evolutions. This study shows that properties of the operator entanglement production are qualitatively similar to the properties reported in literature about the pure state entanglement production. This similarity establishes that the operator entanglement quantifies {\it intrinsic} entangling power of an operator. The term `intrinsic' suggests that this measure is independent of any specific choice of initial states.