The interaction of excited atoms and few-cycle laser pulses

J E Calvert; Han Xu; A J Palmer; R D Glover; D E Laban; X M Tong; A S Kheifets; K Bartschat; I V Litvinyuk; D Kielpinski; R T Sang

doi:10.1038/srep34101

The interaction of excited atoms and few-cycle laser pulses

Sci Rep. 2016 Sep 26:6:34101. doi: 10.1038/srep34101.

Authors

J E Calvert¹, Han Xu¹, A J Palmer¹, R D Glover², D E Laban¹, X M Tong³, A S Kheifets⁴, K Bartschat^{1

5}, I V Litvinyuk¹, D Kielpinski¹, R T Sang¹

Affiliations

¹ Australian Attosecond Science Facility and Centre for Quantum Dynamics, Griffith University, Brisbane, Queensland 4111, Australia.
² Institute for Atomic and Nuclear Physics, University of Liege, Liege 4000, Belgium.
³ Graduate School of Pure and Applied Sciences, and Center for Computational Science, University of Tsukuba, Tsukuba, 305-8571, Japan.
⁴ Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200, Australia.
⁵ Department of Physics and Astronomy, Drake University, Des Moines, IA 50311, USA.

Abstract

This work describes the first observations of the ionisation of neon in a metastable atomic state utilising a strong-field, few-cycle light pulse. We compare the observations to theoretical predictions based on the Ammosov-Delone-Krainov (ADK) theory and a solution to the time-dependent Schrödinger equation (TDSE). The TDSE provides better agreement with the experimental data than the ADK theory. We optically pump the target atomic species and measure the ionisation rate as the a function of different steady-state populations in the fine structure of the target state which shows significant ionisation rate dependence on populations of spin-polarised states. The physical mechanism for this effect is unknown.