Search Results
Interference structure of above-threshold ionization versus above-threshold detachment
2012, Korneev, Ph.A., Popruzhenko, S.V., Goreslavski, S.P., Becker, W., Paulus, G.G., Fetić, B., Milošević, D.B.
Laser-induced electron detachment or ionization of atoms and negative ions is considered. In the context of the saddle-point evaluation of the strong-field approximation (SFA), the velocity maps of the direct electrons (those that do not undergo rescattering) exhibit a characteristic structure due to the constructive and destructive interference of electrons liberated from their parent atoms/ions within certain windows of time. This structure is defined by the above-threshold ionization rings at fixed electron energy and by two sets of curves in momentum space on which destructive interference occurs. The spectra obtained with the SFA are compared with those obtained by numerical solution of the time-dependent Schrödinger equation. For detachment, the agreement is excellent. For ionization, the effect of the Coulomb field is most pronounced for electrons emitted in a direction close to laser polarization, while for nearperpendicular emission the qualitative appearance of the spectrum is unaffected.
Unified description of low-order above-threshold ionization on and off axis
2016, Becker, W., Milošević, D.B.
A recently developed unified description of low-order above-threshold ionization (Becker et al 2014 J. Phys. B: At. Mol. Opt. Phys. 47 204022; 2015 J. Phys. B: At. Mol. Opt. Phys. 48 151001) is revisited and extended. By considering the rescattering electron energies and angles at the classical cutoffs and the contributions of particular quantum-orbit solutions, it is shown that summing both the backward- and the forward-scattering contributions, within the low-frequency approximation, it is possible to reproduce the observed features of the ATI spectra both for low and high energies and both on and off the laser-polarization axis in the momentum plane.
Molecular above-threshold ionization spectra as an evidence of the three-point interference of electron wave packets
2015, Hasović, Elvedin, Milošević, Dejan B., Gazibegović-Busuladži, Azra, Čerkić, Aner, Busuladžić, Mustafa
We consider high-order above-threshold ionization (HATI) of polyatomic molecules ionized by a strong linearly polarized laser field. Improved molecular strong-field approximation by which the HATI process on polyatomic molecular species can be described is developed. Using this theory we calculate photoelectron angular-energy spectra for different triatomic molecules. Special attention is devoted to the minima that are observed in the calculated high-energy electron spectra of the ozone and carbon dioxide molecules. A key difference between these minima and minima that are observed in the corresponding spectra of diatomic molecules are presented.