Beyond the Single-Atom Response in Absorption Line Shapes: Probing a Dense, Laser-Dressed Helium Gas with Attosecond Pulse Trains

Chen Ting Liao, Arvinder Sandhu, Seth Camp, Kenneth J. Schafer, Mette B. Gaarde

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

We investigate the absorption line shapes of laser-dressed atoms beyond the single-atom response, by using extreme ultraviolet (XUV) attosecond pulse trains to probe an optically thick helium target under the influence of a strong infrared (IR) field. We study the interplay between the IR-induced phase shift of the microscopic time-dependent dipole moment and the resonant-propagation-induced reshaping of the macroscopic XUV pulse. Our experimental and theoretical results show that as the optical depth increases, this interplay leads initially to a broadening of the IR-modified line shape, and subsequently, to the appearance of new, narrow features in the absorption line.

Original languageEnglish (US)
Article number143002
JournalPhysical review letters
Volume114
Issue number14
DOIs
StatePublished - Apr 6 2015

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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