Disentangling Spectral Phases of Interfering Autoionizing States from Attosecond Interferometric Measurements
We have determined spectral phases of Ne autoionizing states from extreme ultraviolet and midinfrared attosecond interferometric measurements and ab initio full-electron time-dependent theoretical calculations in an energy interval where several of these states are coherently populated. The retrieved phases exhibit a complex behavior as a function of photon energy, which is the consequence of the interference between paths involving various resonances. In spite of this complexity, we show that phases for individual resonances can still be obtained from experiment by using an extension of the Fano model of atomic resonances. As simultaneous excitation of several resonances is a common scenario in many-electron systems, the present work paves the way to reconstruct electron wave packets coherently generated by attosecond pulses in systems larger than helium ; Work supported by the ERC proof-of-concept Grant No. 780284-Imaging-XChem within the seventh framework program of the European Union, the MINECO Project No. FIS2013-42002-R, the EU-H2020- LASERLABEUROPE-654148, the ANR Projects No. ANR-15-CE30-0001-CIMBAAD, No. ANR-11- EQPX0005-ATTOLAB, and No. ANR-10-LABX-0039- PALM, the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award no. DEGF02-04ER15614, and the NSF Grant No. PHY-1607588. Calculations were performed at CCC-UAM and Marenostrum Supercomputer Center. F. M. acknowledges support from the "Severo Ochoa" Programme for Centres of Excellence in R&D (MINECO, Grant No. SEV-2016- 0686) and the "María de Maeztu" Programme for Units of Excellence in R&D (Grant No. MDM-2014-0377)
