Nondipole effects in atomic dynamic interference

Abstract

Nondipole effects in the atomic dynamic interference are investigated by numerically solving the time-dependent Schrödinger equation (TDSE) of hydrogen. It is found that the inclusion of nondipole corrections in the TDSE can induce momentum shifts of photoelectrons in the opposite direction of the laser propagation. The magnitude of the momentum shift is roughly proportional to the laser peak intensity and to the momentum component of the photoelectron along the laser propagation. By including the nondipole corrections of the Volkov phase into a semi-analytical model previously developed under the dipole approximation, all the main features of the momentum shifts can be nicely reproduced. Through an analytic expression, the origin of such momentum shifts is attributed to the nondipole phase difference between the two electron wave packets ejected in the rising edge and the falling edge, which will interfere with each other and result in the final fringe pattern. One important consequence of such momentum shifts is that they can smooth out the peak splitting induced by the dynamic interference in the photoelectron energy spectrum. Nevertheless, it should be emphasized that the dynamic interference persists in the photoelectron momentum distributions and is not suppressed at all for the laser parameters considered in this work.

Photoelectron momentum distribution of hydrogen atoms in a superintense ultrashort high-frequency pulse

“…Unfortunately, there are minor faults or typos in their models Demekhin et al [13], and Demekhin and Cederbaum [10] and Baghery et al [9] gave contradicting conclusions. However, the time-dependent Schrödinger equation (TDSE) fully numerical solution corroborated some predictions of dynamic interference in photoemission by powerful extreme ultraviolet (XUV) linearly polarized pulses Guo et al [12]; Jiang and Burgdörfer [7]; Wang et al [14]; Wang and Liu [15].…”

Breakdown of the nonrelativistic approximation in superintense laser-matter interactions

“…The dipole approximation greatly simplifies the modeling of the light-matter interaction and as such it is usually the preferred theoretical approach. The validity of the dipole approximation is commonly studied within the context of nonrelativistic quantum mechanics and the time-dependent Schrödinger equation (TDSE) [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. However, in the limit of very high laser intensities, at some point the nonrelativistic TDSE approach cannot be applied and a fully relativistic treatment of the laser-matter interaction is prerequisite [24][25][26][27][28][29][30][31].…”

Laser-induced electron Fresnel diffraction by XUV pulses at extreme intensity

“…It has been shown both experimentally and theoretically that nondipole corrections to the Hamiltonian can induce a photon-momentum transfer to the photoelectron [17][18][19][20][21][22][23]. Besides, when atoms are exposed to the extreme ultraviolet (XUV) pulse of high intensity, the nondipole corrections can alter the dynamic interference [24]. With the further increase of the laser intensity, the nondipole effects become even more remarkable and the photoelectron angular distribution can be largely modified [25] due to the strong interplay between the external electromagnetic and the internal Coulomb forces.…”