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Title: Routes to multiphoton double ionization in combined extreme ultraviolet and infrared laser pulses

Abstract

Xenon multiphoton double ionization pathways are studied in a reaction microscope using a pump-probe arrangement of extreme ultraviolet high harmonic and infrared laser radiation. The momentum of photoelectrons is recorded in coincidence with singly or doubly charged ions. Among all possible routes to multiphoton double ionization, sequential processes using ionic excited states as intermediate steps are clearly identified.

Authors:
; ; ;  [1];  [2];  [3]; ;  [4]
  1. Max-Born-Institute, Max-Born-Strasse 2A, D-12489 Berlin (Germany)
  2. Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States)
  3. (UMR 8624), Batiment 350, Centre d'Orsay, 91405 Orsay Cedex (France)
  4. LIXAM (UMR 8624), Batiment 350, Centre d'Orsay, 91405 Orsay Cedex (France)
Publication Date:
OSTI Identifier:
20982356
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 75; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevA.75.033408; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; EXCITED STATES; EXTREME ULTRAVIOLET RADIATION; INFRARED RADIATION; IONS; LASER RADIATION; MULTI-PHOTON PROCESSES; PHOTOELECTRON SPECTROSCOPY; PHOTOIONIZATION; PHOTON-ATOM COLLISIONS; PULSES; XENON

Citation Formats

Boettcher, M., Rottke, H., Zhavoronkov, N., Sandner, W., Agostini, P., LIXAM, Gisselbrecht, M., and Huetz, A. Routes to multiphoton double ionization in combined extreme ultraviolet and infrared laser pulses. United States: N. p., 2007. Web. doi:10.1103/PHYSREVA.75.033408.
Boettcher, M., Rottke, H., Zhavoronkov, N., Sandner, W., Agostini, P., LIXAM, Gisselbrecht, M., & Huetz, A. Routes to multiphoton double ionization in combined extreme ultraviolet and infrared laser pulses. United States. doi:10.1103/PHYSREVA.75.033408.
Boettcher, M., Rottke, H., Zhavoronkov, N., Sandner, W., Agostini, P., LIXAM, Gisselbrecht, M., and Huetz, A. Thu . "Routes to multiphoton double ionization in combined extreme ultraviolet and infrared laser pulses". United States. doi:10.1103/PHYSREVA.75.033408.
@article{osti_20982356,
title = {Routes to multiphoton double ionization in combined extreme ultraviolet and infrared laser pulses},
author = {Boettcher, M. and Rottke, H. and Zhavoronkov, N. and Sandner, W. and Agostini, P. and LIXAM and Gisselbrecht, M. and Huetz, A.},
abstractNote = {Xenon multiphoton double ionization pathways are studied in a reaction microscope using a pump-probe arrangement of extreme ultraviolet high harmonic and infrared laser radiation. The momentum of photoelectrons is recorded in coincidence with singly or doubly charged ions. Among all possible routes to multiphoton double ionization, sequential processes using ionic excited states as intermediate steps are clearly identified.},
doi = {10.1103/PHYSREVA.75.033408},
journal = {Physical Review. A},
number = 3,
volume = 75,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
  • Photoelectron spectroscopy has been performed to study the multiphoton double ionization of Ar in an intense extreme ultraviolet laser field (h{nu}{approx}21 eV, {approx}5 TW/cm{sup 2}), by using a free electron laser (FEL). Three distinct peaks identified in the observed photoelectron spectra clearly show that the double ionization proceeds sequentially via the formation of Ar{sup +}: Ar+h{nu}{yields}Ar{sup +}+e{sup -} and Ar{sup +}+2h{nu}{yields}Ar{sup 2+}+e{sup -}. Shot-by-shot recording of the photoelectron spectra allows simultaneous monitoring of FEL spectrum and the multiphoton process for each FEL pulse, revealing that the two-photon ionization from Ar{sup +} is significantly enhanced by intermediate resonances in Ar{sup +}.
  • Two-photon double ionization (TPDI) of D{sub 2} is studied for 38-eV photons at the Free Electron Laser in Hamburg (FLASH). Based on model calculations, instantaneous and sequential absorption pathways are identified as separated peaks in the measured D{sup +}+D{sup +} fragment kinetic energy release (KER) spectra. The instantaneous process appears at high KER, corresponding to ionization at the molecule's equilibrium distance, in contrast to sequential ionization mainly leading to low-KER contributions. Measured fragment angular distributions are in good agreement with theory.
  • We report the results of experimental and theoretical investigations of the two-color, two-photon ionization of Ar atoms, using femtosecond pulses of infrared laser radiation in combination with its extreme-ultraviolet harmonics. It is shown that the intensities of the photoelectron lines resulting from the absorption of photons from both fields strongly depend both on the respective phases of the fields and on atomic quantities such as the asymmetry parameter. These phases, which are notoriously difficult to measure, can be estimated by changing the polarization state of the laser radiation.
  • Laser-driven expansion of pure-tin microdroplets was demonstrated to produce an efficient and low-debris extreme-ultraviolet (EUV) light source. The pre-expansion is indispensable for resolving the considerable mismatch between the optimal laser spot diameter ({approx}300 {mu}m) and the diameter ({approx}20 {mu}m) of microdroplets containing the minimum-mass Sn fuel for generating the required EUV radiant energy ({approx}10 mJ/pulse). Explosive expansion of microdroplets was attained by using a laser prepulse, whose intensity was at least 3x10{sup 11} W/cm{sup 2}. The expanded microdroplet was irradiated with a CO{sub 2} laser pulse to generate EUV light. A combination of low density and long-scale length of themore » expanded microdroplet leads to a higher EUV energy conversion efficiency (4%) than that (2.5%) obtained from planar Sn targets irradiated by a single CO{sub 2} laser pulse. This scheme can be used to produce a practical EUV light source system.« less