464 / 2019-03-14 17:15:16

Dynamic Interference in Photoemission by Superintense Ultrashort Extreme Ultraviolet Pulses

Dynamical interference,Ac Stark shifts,Atomic stabilization,Superintense laser field

全体主题 > Fundamental Physics at Extremes

When subjected to the superintense linear polarized laser field with high frequency, dynamical interference (DI) in photoionization occurs when electron emission from equally ac Stark-shifted levels at the rising and falling temporal pulses profile interfere and are temporally separated by a time interval of intense-field stabilization against photoemission [1, 2, 3]. In particular, DI from the ground state of hydrogen atoms has been the subject of a controversy between theoretical predictions [4, 5].
By solving the time-dependent Schrodinger equation, we investigated DI for emission from ground-state hydrogen atoms in the presence of laser pulses with circular and elliptical polarization [6] and chirped pulses. Including ac Stark shifts and atomic stabilization, our numerical results confirm that dynamic interference is possible for single-XUV-photon ionization from the hydrogen ground.
We found that DI from ground state atomic hydrogen can (i) occur for photoionization by elliptically polarized ultra-fast laser pulses, (ii) be approximated within first-order perturbation theory for peak intensities up to 1018W/cm2, while higher intensities require a non-perturbative approach, and (iii) compared with chirp-free pulses, we find that the interference structure in photoemission spectra is increasingly red shifted for positively and negatively chirped pulses as the pulse peak intensity and duration increase, while the interference structure becomes either less pronounced or significantly narrower.
This work is supported by the NSFC under Grant Nos. 11774131, 91850114, 11604119 and, in part, by the US DOE under Award No. DE-FG02-86ER13491 and US NSF Grant PHY 1802085.
[1] J. H. Eberly and K. C. Kulander, Science 262, 5137 (1993)
[2] J. Guo, F. Guo, J. Chen and Y. Yang, Acta Phys. Sin. 67, 073202 (2018)
[3] W. Jiang and J. Burgdorfer, Opt. Express 26, 19921 (2018)
[4] P. V. Demekhin and L. S. Cederbaum 2012 Phys. Rev. Lett. 108 253001
[5] M. Baghery et al. 2017 Phys. Rev. Lett. 118 143202
[6] N. Wang, G. Li, A. Liu, and U. Thumm, to be published