Abstract

The even and odd high-order harmonic generation in a modeled hydrogen molecular ion in strong laser fields is studied by numerically simulating the time-dependent Schrödinger equation. By applying a linearly polarized laser pulse whose polarization axis is perpendicular to the molecular axis, the pure odd harmonics polarized along the laser polarization direction are produced. Meanwhile, the pure even harmonics polarized along the molecular axis may be produced simultaneously either by adding an extra weak direct-current electric field along the molecular axis, or by artificially setting asymmetric charges for the two nuclei. The Bohmian trajectories reveal that the pure even harmonics are contributed by the dipole formed by the asymmetric expansion of the ionized wave packet along the molecular axis, instead of the asymmetric Coulomb attraction for the rescattering electron as expected. Moreover, the relationship between the symmetry of molecular orbital and the parity of high-order harmonics is also explored.

© 2019 Optical Society of America

Roles of Coulomb potentials in below- and above-threshold harmonic generation for a hydrogen atom in strong laser fields

Lu-Ning Li, Jun-Ping Wang, and Feng He
J. Opt. Soc. Am. B 33(7) 1558-1563 (2016)

Dressed-bound-state molecular strong-field approximation: application to high-order harmonic generation by heteronuclear diatomic molecules

Senad Odžak and Dejan B. Milošević
J. Opt. Soc. Am. B 29(8) 2147-2155 (2012)

Routes of odd-even harmonic emission from oriented polar molecules

Xuejiao Xie, Shujuan Yu, Weiyan Li, Shang Wang, and Yanjun Chen
Opt. Express 26(14) 18578-18596 (2018)

Control of the high harmonic generation spectra by changing the molecule-laser field relative orientation

Rosalba Daniele, Francesca Morales, Giuseppe Castiglia, Pietro Paolo Corso, Gianfranco Orlando, and Emilio Fiordilino
J. Opt. Soc. Am. B 27(4) 625-630 (2010)

Wavelength scaling laws for high-order harmonic yield from atoms driven by mid- and long-wave infrared laser fields

A. S. Emelina, M. Yu. Emelin, and M. Yu. Ryabikin
J. Opt. Soc. Am. B 36(11) 3236-3245 (2019)