High-order above-threshold ionization of argon: plateau resonances and the Floquet quasienergy spectrum

Potvliege, R.M.; Vucic, S.

doi:10.1103/physreva.74.023412

High-order above-threshold ionization of argon: plateau resonances and the Floquet quasienergy spectrum

Potvliege, R.M.; Vucic, S.

Authors

Dr Robert Potvliege r.m.potvliege@durham.ac.uk
Associate Professor

S. Vucic

Abstract

The Floquet quasienergy spectrum of argon in a strong laser field of 800 nm wavelength is calculated for intensities up to 7×1013 W cm–2, and beyond for some states, using a discrete complex basis set. Many of the dressed excited states of interest shift nonponderomotively in complicated ways but keep an ionization width narrow enough to produce sharp enhancements of above-threshold ionization (ATI) through Stark-shift-induced resonances. The quasienergy map is compared to high-resolution ATI spectra for 120 fs Ti:sapphire pulses [Nandor et al., Phys. Rev. A 60, R1771 (1999)]. The plateau enhancements happen at intensities where the dressed ground state is in resonance or in the wing of resonances with dressed excited states. The resonant dressed states are identified. In many cases, the same state is responsible for an enhancement of ATI in the low as well as the high orders. No evidence is found for enhancements that are not concomitant with any curve crossing and could thereby be interpreted as channel-closing enhancement.

Citation

Potvliege, R., & Vucic, S. (2006). High-order above-threshold ionization of argon: plateau resonances and the Floquet quasienergy spectrum. Physical Review A, 74(2), https://doi.org/10.1103/physreva.74.023412

Journal Article Type	Article
Publication Date	2006-08
Deposit Date	Feb 12, 2007
Publicly Available Date	Sep 20, 2010
Journal	Physical Review A
Print ISSN	1050-2947
Electronic ISSN	1094-1622
Publisher	American Physical Society
Peer Reviewed	Peer Reviewed
Volume	74
Issue	2
DOI	https://doi.org/10.1103/physreva.74.023412
Keywords	MULTIPHOTON PROCESSES; HARMONIC-GENERATION; ATOMIC-HYDROGEN; LASERFIELD; 248 NM; ENHANCEMENT; STATES; TIME; DYNAMICS; HELIUM