Direct extraction of intense-field-induced polarization in the continuum on the attosecond time scale from transient absorption

Abstract

Author(s): Li, X; Haxton, DJ; Gaarde, MB; Schafer, KJ; McCurdy, CW | Abstract: A procedure is suggested for using transient absorption spectroscopy above the ionization threshold to measure the polarization of the continuum induced by an intense optical pulse. In this way transient absorption measurement can be used to probe subfemtosecond intense field dynamics in atoms and molecules. The method is based on an approximation to the dependence of these spectra on time delay between an attosecond XUV probe pulse and an intense pump pulse that is tested over a wide range of intensities and time delays by all-electrons-active calculations using the multiconfiguration time-dependent Hartree-Fock method in the case of neon.