Prediction of attosecond light pulses in the VUV range in a high-order-harmonic-generation regime

Abstract

Attosecond light pulses within the vacuum ultraviolet (VUV) energy range are predicted by solving the time-dependent Schrödinger equation (TDSE) for a model neon atom in short laser pulses of different field polarization states. We compare high-order harmonic generation in linearly polarized laser pulses to the method of polarization gating and find attosecond pulses that approach the Fourier limit of 700 as given by an indium filter, spectrally centered at 15 eV. At such low energies, harmonic generation has low sensitivity to ellipticity, which enables the generation of elliptically polarized attosecond pulses. We also show that emission at the atomic transition energies is strongly damped by including intensity averaging.

Half-cycle cutoff in near-threshold harmonic generation

“…For example, the perturbation theory [20] diverges when the laser intensity increases [21] and the SFA cannot correctly describe low-energy electrons as it ignores the potential [18]. Thus the theoretical study of low-energy harmonics mostly relies on the numerical solution to the time-dependent Schrödinger equation (TDSE) [19,22,23]. A rough understanding is mainly based on the simple man's model with the potential only accommodated in the propagation step [24,25].…”

Single-Photon Laser-Enabled Auger Spectroscopy for Measuring Attosecond Electron-Hole Dynamics

“…The probe VUV pulses with the needed properties can be generated by HHG in krypton and subsequent spectral filtering [28]. As illustrated by our detailed ab initio calculations for two qualitatively different hole migration modes in glycine, the VUV spLEAD probe efficiently maps ultrafast hole migration dynamics onto the double ionization yield with no competing processes contributing to the doubly charged ion signal.…”

Unravelling the dynamical origin of below- and near-threshold harmonic generation of H2+ in an intense NIR laser field

“…High-order-harmonic generation (HHG) is a fundamental atomic and molecular process in strong laser fields that continues to receive considerable attention and it plays a crucial role in the development of ultrafast science and technology12. Significant application of the HHG technology includes the generation of ultrashort attosecond pulses345 and ultrafast molecular imaging67, etc., to name only a few.…”

“…Significant application of the HHG technology includes the generation of ultrashort attosecond pulses345 and ultrafast molecular imaging67, etc., to name only a few. The availability of the attosecond pulse further allows the direct detection and control of the electronic dynamics in atoms, molecules and condensed matter systems235678910. The HHG spectrum is characterized by a rapid drop in intensity at low orders followed by a broad plateau and then a cutoff at approximately I p  + 3.17  U p , where I p is the ionization potential of the atom/molecule and U p is the ponderomotive potential.…”

“…More recently considerable attention has been paid to the near- and below-threshold regimes141516171819202122 as a potential source of coherent vacuum-ultraviolet radiation2. In these lower-energy regimes, the conventional three-step model and the SFA become inadequate, since they neglect the Coulomb potential and the detailed electronic structure of the target atom/molecule.…”