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Full-Text Articles in Physics
Attosecond Streaking In The Low-Energy Region As A Probe Of Rescattering, Ming-Hui Xu, Liang-You Peng, Zheng Zhang, Qihuang Gong, Xiao-Min Tong, Evgeny A. Pronin, Anthony F. Starace
Attosecond Streaking In The Low-Energy Region As A Probe Of Rescattering, Ming-Hui Xu, Liang-You Peng, Zheng Zhang, Qihuang Gong, Xiao-Min Tong, Evgeny A. Pronin, Anthony F. Starace
Anthony F. Starace Publications
The dynamics of low-energy photoelectrons (PEs) ionized by a single attosecond pulse in the presence of an intense infrared (IR) laser field is investigated. Whereas attosecond streaking usually involves momentum shifts of high-energy PEs, when PEs have low initial kinetic energies, the IR field can control the continuum-electron dynamics by inducing PE scattering from the residual ion. A semiclassical model is used to show that particular PE trajectories in the continuum involving electron-ion scattering explain the interference patterns exhibited in the low-energy PE spectrum. We confirm the effects of the trajectories by means of a full quantum simulation.
Two-Photon Double Ionization Of Helium: Evolution Of The Joint Angular Distribution With Photon Energy And Two-Electron Energy Sharing, Zheng Zhang, Liang-You Peng, Ming-Hui Xu, Anthony F. Starace, Toru Morishita, Qihuang Gong
Two-Photon Double Ionization Of Helium: Evolution Of The Joint Angular Distribution With Photon Energy And Two-Electron Energy Sharing, Zheng Zhang, Liang-You Peng, Ming-Hui Xu, Anthony F. Starace, Toru Morishita, Qihuang Gong
Anthony F. Starace Publications
Ab initio calculations of two-photon double ionization of helium with photon energies varying from the nonsequential regime to well above the double-ionization threshold are presented. A systematic study of the joint angular distributions of the two ionized electrons at different energy sharing shows that the role of electron correlations is imprinted in the joint angular distribution. In particular, a rather general pattern is identified in the nonsequential regime that is independent of photon energy, pulse length, and energy sharing between the two electrons. Interestingly, the same distribution pattern is found for the equal-energy-sharing case, even when the photon energy is …
Perturbation-Theory Analysis Of Ionization By A Chirped Few-Cycle Attosecond Pulse, Evgeny A. Pronin, Anthony F. Starace, Liang-You Peng
Perturbation-Theory Analysis Of Ionization By A Chirped Few-Cycle Attosecond Pulse, Evgeny A. Pronin, Anthony F. Starace, Liang-You Peng
Anthony F. Starace Publications
The angular distribution of electrons ionized from an atom by a chirped few-cycle attosecond pulse is analyzed using perturbation theory (PT), keeping terms in the transition amplitude up to second order in the pulse electric field. The dependence of the asymmetry in the ionized electron distributions on both the chirp and the carrier-envelope phase (CEP) of the pulse are explained using a simple analytical formula that approximates the exact PT result. This approximate formula (in which the chirp dependence is explicit) reproduces reasonably well the chirp-dependent oscillations of the electron angular distribution asymmetries found numerically by Peng et al. [Phys. …
Evidence Of The 2S2 P(1P) Doubly Excited State In The Harmonic Generation Spectrum Of Helium, Jean Marcel Ngoko Djiokap, Anthony F. Starace
Evidence Of The 2S2 P(1P) Doubly Excited State In The Harmonic Generation Spectrum Of Helium, Jean Marcel Ngoko Djiokap, Anthony F. Starace
Anthony F. Starace Publications
By solving the two-active-electron time-dependent Schrödinger equation in an intense, ultrashort laser field, we investigate evidence of electron correlations in the high-order harmonic generation spectrum of helium. As the frequency of the driving laser pulse varies from 4.6 to 6.6 eV, the 13th, 11th, and 9th harmonics sequentially become resonant with the transition between the ground state and the isolated 2s2p(1P) autoionizing state of helium, which dramatically enhances these harmonics and changes their profiles. When each of the 9th and 13th harmonics are in resonance with this autoionizing state, there is also a …
Analytic Confirmation That The Factorized Formula For Harmonic Generation Involves The Exact Photorecombination Cross Section, M. V. Frolov, N. L. Manakov, T. S. Sarantseva, Anthony F. Starace
Analytic Confirmation That The Factorized Formula For Harmonic Generation Involves The Exact Photorecombination Cross Section, M. V. Frolov, N. L. Manakov, T. S. Sarantseva, Anthony F. Starace
Anthony F. Starace Publications
High-order-harmonic generation (HHG) by atoms in a strong laser field is analyzed theoretically, taking into account atomic potential effects beyond the strong field approximation (SFA). Our analytical derivation extends the time-dependent effective range (TDER) theory, developed previously for a short-range potential supporting only a single bound state, to the case of a potential supporting two bound states having different angular momenta and dynamically interacting with the continuum. In contrast to the SFA and the single-state TDER model, in both of which the HHG rates in the region of the high-energy plateau cutoff involve only the plane-wave (first Born) approximation for …
High-Order Harmonic Generation By Atoms In A Few-Cycle Laser Pulse: Carrier-Envelope Phase And Many-Electron Effects, M. V. Frolov, N. L. Manakov, A. A. Silaev, N. V. Vvedenskii, Anthony F. Starace
High-Order Harmonic Generation By Atoms In A Few-Cycle Laser Pulse: Carrier-Envelope Phase And Many-Electron Effects, M. V. Frolov, N. L. Manakov, A. A. Silaev, N. V. Vvedenskii, Anthony F. Starace
Anthony F. Starace Publications
Analytic formulas describing high-order harmonic generation (HHG) by atoms in a short laser pulse are obtained quantum mechanically in the tunneling limit. These results provide analytic expressions of the three-step HHG scenario, as well as of the returning electron wave packet, in a few-cycle pulse. Our results agree well with those of numerical solutions of the time-dependent Schrödinger equation for the H atom, while for Xe they predict many-electron atomic dynamics features in few-cycle HHG spectra and significant dependence of these features on the carrier-envelope phase of a laser pulse.
Decay Of A Negative Molecular Ion In A Constant Electric Field, S. V. Borzunov, N. L. Manakov, Anthony F. Starace, M. V. Frolov
Decay Of A Negative Molecular Ion In A Constant Electric Field, S. V. Borzunov, N. L. Manakov, Anthony F. Starace, M. V. Frolov
Anthony F. Starace Publications
The problem of the shift and broadening of the electron energy levels in the field of two 3D short-range potentials (e.g., the model of a negative molecular ion) by a constant electric field F is considered. The interaction of an electron with attraction centers is taken into account in the effective range approximation. We analyze the cases when both centers maintain weakly bound s states and when the electron state in the field of one of the centers is a p state. Exact numerical results for the shift and the width of the energy levels of a quasi-molecule as functions …