Generation of attosecond pulse pair in polar media by chirped few-cycle pulses

Abstract

The high-order harmonic generation in a polar medium driven by an initially chirped few-cycle laser pulse is investigated via numerically solving the nonlinear Bloch or Maxwell-Bloch equations based on whether propagation effects are taken into account or not. As a result of the reduction of quantum trajectories number due to the introduction of chirps, an attosecond pulse pair (APP) is generated instead of a general attosecond pulse train. Moreover, the time delay between the two attosecond pulses is tunable. When propagation effects take roles, the peak intensities of the APP can be enhanced at suitable propagation distances without observable duration broadening, and such an enhancement can be modulated by changing medium density.

Attosecond lighthouse above 100 eV from high-harmonic generation of mid-infrared pulses

“…A complete recent review on the field can be found, for instance, in [33]. Current research also emphasizes the possibility to produce a pair of attosecond pulses (APPs) with controllable delay between them [34]; these APPs being more advantageous for performing attosecond pump-probe measurements.…”

Pulse amplification in a closed-loop Λ system with permanent dipole moments

“…But in the case of noncentrosymmetric molecules, due to broken spatial symmetry, ψs are neither odd nor even therefore both single and two-photon excitation is possible for the same transition. In addition to multi-photon excitation, the breaking of spatial symmetry due to presence of PDM leads to higher harmonic generation in two-level system [18], having application in attosecond pulse generation [19], and enhancement of many well known nonlinear effects [20].…”