Autoionizing polariton stabilization in attosecond transient absorbtion

Intense laser pulses can couple resonances in the continuum, giving rise to a split pair of autoionizing polaritons whose lifetime can be extended as a result of interference between radiative and Auger decay channels [1]. We study this phenomenon both analytically and computationally by simulating ab initio attosecond transient absorption in argon. The calculated spectra exhibit multiple avoided crossings between the 3s^-14p autoionizing resonance and light-induced states originating from other resonances. These avoided crossings, which are characteristic of the formation of a polaritonic multiplet, clearly indicate that some polaritons are stabilized against autoionization. Using an extension of the Jaynes-Cummings model to autoionizing states [2], we confirm that this stabilization is due to the destructive interference between radiative and Auger decay channels. These theoretical predictions are in excellent agreement with recent experiments conducted in parallel.  This study indicates a new way to control the electronic structure in the continuum of poly-electronic systems.

[1] Y.  S.  Kim  and  P.  Lambropoulos,  Phys.  Rev.  Lett.  49, 1698 (1982)

[2]  E. T. Jaynes and F. W. Cummings, Proceedings of the IEEE 51, 89 (1963)