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University of Nebraska - Lincoln

Anthony F. Starace Publications

2009

Articles 1 - 7 of 7

Full-Text Articles in Physics

Perturbation Theory Analysis Of Attosecond Photoionization, Anthony F. Starace, Evgeny A. Pronin, M. V. Frolov, N. L. Manakov Dec 2009

Perturbation Theory Analysis Of Attosecond Photoionization, Anthony F. Starace, Evgeny A. Pronin, M. V. Frolov, N. L. Manakov

Anthony F. Starace Publications

Ionization of an atom by a few-cycle attosecond xuv pulse is analyzed using perturbation theory (PT), keeping terms in the transition amplitude up to second order in the pulse electric field. Within the PT approach, we present an ab initio parametrization of the ionized electron angular distribution (AD) using rotational invariance and symmetry arguments. This parametrization gives analytically the dependence of the AD on the carrier envelope phase (CEP), the polarization of the pulse, and on the ionized electron momentum direction, p^ . For the general case of an elliptically polarized pulse, we show that interference of the first- and …


Few-Cycle Attosecond Pulse Chirp Effects On Asymmetries In Ionized Electron Momentum Distributions, Liang-You Peng, Fang Tan, Qihuang Gong, Evgeny A. Pronin, Anthony F. Starace Jul 2009

Few-Cycle Attosecond Pulse Chirp Effects On Asymmetries In Ionized Electron Momentum Distributions, Liang-You Peng, Fang Tan, Qihuang Gong, Evgeny A. Pronin, Anthony F. Starace

Anthony F. Starace Publications

The momentum distributions of electrons ionized from H atoms by chirped few-cycle attosecond pulses are investigated by numerically solving the time-dependent Schrödinger equation. The central carrier frequency of the pulse is chosen to be 25 eV, which is well above the ionization threshold. The asymmetry (or difference) in the yield of electrons ionized along and opposite to the direction of linear laser polarization is found to be very sensitive to the pulse chirp (for pulses with fixed carrier-envelope phase), both for a fixed electron energy and for the energy-integrated yield. In particular, the larger the pulse chirp, the larger the …


Analytic Description Of The High-Energy Plateau In Harmonic Generation By Atoms: Can The Harmonic Power Increase With Increasing Laser Wavelengths?, M. V. Frolov, N. L. Manakov, T. S. Sarantseva, M. Yu. Emelin, M. Yu. Ryabikin, Anthony F. Starace Jun 2009

Analytic Description Of The High-Energy Plateau In Harmonic Generation By Atoms: Can The Harmonic Power Increase With Increasing Laser Wavelengths?, M. V. Frolov, N. L. Manakov, T. S. Sarantseva, M. Yu. Emelin, M. Yu. Ryabikin, Anthony F. Starace

Anthony F. Starace Publications

A closed-form analytic formula for high-order harmonic generation (HHG) rates for atoms (that generalizes an HHG formula for negative ions [M.V. Frolov et al., J. Phys. B 42, 035601 (2009)]) is used to study laser wavelength scaling of the HHG yield for harmonic energies in the cutoff region of the HHG plateau. We predict increases of the harmonic power for HHG by Ar, Kr, and Xe with increasing wavelength λ over atom-specific intervals of λ in the infrared region, λ ~ (0.8–2.0) μm.


Analytic Formulas For Above-Threshold Ionization Or Detachment Plateau Spectra, M. V. Frolov, N. L. Manakov, Anthony F. Starace Mar 2009

Analytic Formulas For Above-Threshold Ionization Or Detachment Plateau Spectra, M. V. Frolov, N. L. Manakov, Anthony F. Starace

Anthony F. Starace Publications

Closed-form analytic formulas are derived in the tunneling limit for both above-threshold detachment (ATD) of negative ions and above-threshold ionization (ATI) of neutral atoms. These formulas are shown to give precise agreement with essentially exact single-active-electron numerical results for detached or ionized electron energies corresponding to the high-energy end of the ATD and ATI plateaus (with only a small constant shift of electron energies being required in the case of ATI). These formulas for ATI and ATD rates thus provide an analytic explanation for the well-known oscillatory patterns of ATI and ATD rates as functions of electron energy and of …


Plateau Structure In Resonant Laser-Assisted Electron-Atom Scattering, A. V. Flegel, M. V. Frolov, N. L. Manakov, Anthony F. Starace Mar 2009

Plateau Structure In Resonant Laser-Assisted Electron-Atom Scattering, A. V. Flegel, M. V. Frolov, N. L. Manakov, Anthony F. Starace

Anthony F. Starace Publications

Orders of magnitude increases are predicted in the cross sections for electron-atom scattering accompanied by absorption or emission of n laser photons for incident electron energies at which the electron, by emitting μ laser photons, can be captured by the atom to form a negative ion. Enhancements are most significant in the plateau region (n >> μ) of the scattered electron spectrum, whose shape is predicted to replicate that of the ion’s (n + μ)-photon detachment spectrum.


Analytic Formulae For High Harmonic Generation, M. V. Frolov, N. L. Manakov, T. S. Sarantseva, Anthony F. Starace Jan 2009

Analytic Formulae For High Harmonic Generation, M. V. Frolov, N. L. Manakov, T. S. Sarantseva, Anthony F. Starace

Anthony F. Starace Publications

Analytic formulae describing harmonic generation by a weakly bound electron are derived quantum mechanically in the tunneling limit. The formulae confirm the classical three-step model and provide an analytic explanation for oscillatory structures on the harmonic generation plateau.


Preface To The Proceedings Of The Xxvi International Conference On Photonic, Electronic And Atomic Collisions, Ann Orel, Anthony F. Starace, Dragan Nikolić, Nora Berrah, Thomas Gorczyca, Emanuel Kamber, John A. Tanis Jan 2009

Preface To The Proceedings Of The Xxvi International Conference On Photonic, Electronic And Atomic Collisions, Ann Orel, Anthony F. Starace, Dragan Nikolić, Nora Berrah, Thomas Gorczyca, Emanuel Kamber, John A. Tanis

Anthony F. Starace Publications

The XXVIth International Conference on Photonic, Electronic and Atomic Collisions was held on the campus of Western Michigan University (WMU) in Kalamazoo during 22-28 July 2009. Kalamazoo, the home of a major state university amid pleasant surroundings, was a delightful place for the conference. The 473 scientific participants, 111 of whom were students, had many fruitful discussions and exchanges that contributed to the success of the conference. Participants from 43 countries made the conference truly international in scope.

The plenary lectures and the progress and special reports bridged the gap between the different fields of collision physics, making it possible …