Laser-assisted dynamic interference in double ionization of helium
Phys. Rev. A 113, 043122 – Published 17 April, 2026
DOI: https://doi.org/10.1103/w5ls-g47d
Abstract
We theoretically study the double ionization of helium atom induced by an ultrashort extreme ultraviolet (XUV) pulse with the photon energy above the double-ionization threshold in the presence of an infrared (IR) laser pulse. By numerically solving the reduced-dimensional time-dependent Schrödinger equation (TDSE), we obtain the joint energy spectra of the two photoelectrons, in which peak splittings are observed both in the main band where one XUV photon is absorbed and in the sidebands where additional IR photons are either absorbed or emitted. A simple laser-assisted dynamic interference (LADI) model, based on the strong-field approximation (SFA) and neglecting the electron-electron correlation, accurately reproduces the numerical TDSE results regarding the peak splittings in the total energy spectra. Additionally, peak-splitting structures arising from the dynamic multiphoton interference (DMPI) mechanism are identified in the joint energy spectra. The DMPI is revealed by excluding the key LADI phase term in the SFA formula. We find that the DMPI is sensitive to the energy sharing between the two photoelectrons, and its contribution to peak splitting is likely smeared out in the total energy spectrum.
