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Theoretical Study of the Transparency-like Phenomena in the XUV Induced by Coherent Coupling of the Doubly Excited States in Helium

XSD/AMO Special Presentation
Michal Tarana, Purdue University
January 17, 2013 2:00PM to 3:00PM
Building 401, Room A1100
Presently there is great interest in the application of light in the X-ray regime, produced by high-order harmonics, to investigate novel coherent X-ray optical phenomena. Loh et al. [1] report the observation of EIT-like behavior in the extreme ultraviolet (XUV) by coherent coupling of 2s2p and 2p2 doubly excited states in He, probing with laser-produced high-order harmonics. The EIT-like phenomenon observed in their work is characterized solely by an increase in transmission over the entire unperturbed lineshape. It is the aim of our work [2] to extend the phenomenological theoretical treatment of this effect included in [1]. We present calculations based on the solution of the time-dependent Schrodinger equation in the LS-coupling configuration interaction basis set. The absorbing boundary is represented by the complex absorbing potential and we present here the analysis of the ionization yield obtained. This approach allows for more accurate treatment of the ionization continuum than presented in [1].

[1] Z.H. Loh, C.H. Greene and S.R. Leone, Chem. Phys. 350, 7 (2008).
[2] M. Tarana, C.H. Greene, Phys. Rev. A 85, 013411 (2012).