Effects of ultrashort laser pulses on angular distributions of photoionization spectra

Raymond Ooi, C.H. and Ho, W.L. and Bandrauk, A.D. (2017) Effects of ultrashort laser pulses on angular distributions of photoionization spectra. Scientific Reports, 7 (1). p. 6739. ISSN 2045-2322, DOI https://doi.org/10.1186/s11671-016-1793-y.

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Abstract

We study the photoelectron spectra by intense laser pulses with arbitrary time dependence and phase within the Keldysh framework. An efficient semianalytical approach using analytical transition matrix elements for hydrogenic atoms in any initial state enables efficient and accurate computation of the photoionization probability at any observation point without saddle point approximation, providing comprehensive three dimensional photoelectron angular distribution for linear and elliptical polarizations, that reveal the intricate features and provide insights on the photoionization characteristics such as angular dispersions, shift and splitting of photoelectron peaks from the tunneling or above threshold ionization(ATI) regime to non-adiabatic(intermediate) and multiphoton ionization(MPI) regimes. This facilitates the study of the effects of various laser pulse parameters on the photoelectron spectra and their angular distributions. The photoelectron peaks occur at multiples of 2Latin small letter h with strokeω for linear polarization while odd-ordered peaks are suppressed in the direction perpendicular to the electric field. Short pulses create splitting and angular dispersion where the peaks are strongly correlated to the angles. For MPI and elliptical polarization with shorter pulseï¿sï¿ the peaks split into doublets and the first peak vanishes. The carrier envelope phase(CEP) significantly affects the ATI spectra while the Stark effect shifts the spectra of intermediate regime to higher energies due to interference.

Item Type:	Article
Funders:	University of Malaya (UM)/Ministry of Education (MOE) High Impact Research (HIR): Grant No. UM.C/625/1/HIR/MoE/CHAN/04
Uncontrolled Keywords:	Ultrashort laser pulses; Angular distributions; Photoionization spectra
Subjects:	Q Science > Q Science (General) Q Science > QC Physics
Divisions:	Faculty of Science
Depositing User:	Ms. Juhaida Abd Rahim
Date Deposited:	08 Aug 2018 04:04
Last Modified:	08 Aug 2018 04:04
URI:	http://eprints.um.edu.my/id/eprint/18992

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