skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Multiphoton ionization of the calcium atom by linearly and circularly polarized laser fields

Abstract

We theoretically study multiphoton ionization of the Ca atom irradiated by the second (photon energy 3.1 eV) and third (photon energy 4.65 eV) harmonics of Ti:sapphire laser pulses (photon energy 1.55 eV). Because of the dense energy level structure the second and third harmonics of a Ti:sapphire laser are nearly single-photon resonant with the 4s4p {sup 1}P{sup o} and 4s5p {sup 1}P{sup o} states, respectively. Although two-photon ionization takes place through the near-resonant intermediate states with the same symmetry in both cases, it turns out that there are significant differences between them. The photoelectron energy spectra exhibit the absence or presence of substructures. More interestingly, the photoelectron angular distributions clearly show that the main contribution to the ionization processes by the third harmonic arises from the far-off-resonant 4s4p {sup 1}P{sup o} state rather than the near-resonant 4s5p {sup 1}P{sup o} state. These findings can be attributed to the fact that the dipole moment for the 4s{sup 2} {sup 1}S{sup e}-4s5p {sup 1}P{sup o} transition is much smaller than that for the 4s{sup 2} {sup 1}S{sup e}-4s4p {sup 1}P{sup o} transition.

Authors:
;  [1]
  1. Institute for Space Sciences, P.O. Box MG-23, 077125 Bucharest-Magurele (Romania)
Publication Date:
OSTI Identifier:
21408654
Resource Type:
Journal Article
Journal Name:
Physical Review. A
Additional Journal Information:
Journal Volume: 81; Journal Issue: 4; Other Information: DOI: 10.1103/PhysRevA.81.043418; (c) 2010 The American Physical Society; Journal ID: ISSN 1050-2947
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ANGULAR DISTRIBUTION; ATOMS; CALCIUM; DIPOLE MOMENTS; ENERGY LEVELS; ENERGY SPECTRA; EV RANGE; HARMONICS; INTERMEDIATE STATE; LASER RADIATION; LASERS; PHOTOIONIZATION; PHOTONS; PULSES; SAPPHIRE; SYMMETRY; ALKALINE EARTH METALS; BOSONS; CORUNDUM; DISTRIBUTION; ELECTROMAGNETIC RADIATION; ELEMENTARY PARTICLES; ELEMENTS; ENERGY RANGE; IONIZATION; MASSLESS PARTICLES; METALS; MINERALS; OSCILLATIONS; OXIDE MINERALS; RADIATIONS; SPECTRA

Citation Formats

Buica, Gabriela, Nakajima, Takashi, and Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011. Multiphoton ionization of the calcium atom by linearly and circularly polarized laser fields. United States: N. p., 2010. Web. doi:10.1103/PHYSREVA.81.043418.
Buica, Gabriela, Nakajima, Takashi, & Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011. Multiphoton ionization of the calcium atom by linearly and circularly polarized laser fields. United States. doi:10.1103/PHYSREVA.81.043418.
Buica, Gabriela, Nakajima, Takashi, and Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011. Thu . "Multiphoton ionization of the calcium atom by linearly and circularly polarized laser fields". United States. doi:10.1103/PHYSREVA.81.043418.
@article{osti_21408654,
title = {Multiphoton ionization of the calcium atom by linearly and circularly polarized laser fields},
author = {Buica, Gabriela and Nakajima, Takashi and Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011},
abstractNote = {We theoretically study multiphoton ionization of the Ca atom irradiated by the second (photon energy 3.1 eV) and third (photon energy 4.65 eV) harmonics of Ti:sapphire laser pulses (photon energy 1.55 eV). Because of the dense energy level structure the second and third harmonics of a Ti:sapphire laser are nearly single-photon resonant with the 4s4p {sup 1}P{sup o} and 4s5p {sup 1}P{sup o} states, respectively. Although two-photon ionization takes place through the near-resonant intermediate states with the same symmetry in both cases, it turns out that there are significant differences between them. The photoelectron energy spectra exhibit the absence or presence of substructures. More interestingly, the photoelectron angular distributions clearly show that the main contribution to the ionization processes by the third harmonic arises from the far-off-resonant 4s4p {sup 1}P{sup o} state rather than the near-resonant 4s5p {sup 1}P{sup o} state. These findings can be attributed to the fact that the dipole moment for the 4s{sup 2} {sup 1}S{sup e}-4s5p {sup 1}P{sup o} transition is much smaller than that for the 4s{sup 2} {sup 1}S{sup e}-4s4p {sup 1}P{sup o} transition.},
doi = {10.1103/PHYSREVA.81.043418},
journal = {Physical Review. A},
issn = {1050-2947},
number = 4,
volume = 81,
place = {United States},
year = {2010},
month = {4}
}