Attosecond transient absorption of a bound wave packet coupled to a smooth continuum
Here, we investigate the possibility of using transient absorption of a coherent bound electron wave packet in hydrogen as an attosecond pulse characterization technique. In a recent work, we have shown that photoionization of such a coherent bound electron wave packet opens up for pulse characterization with unprecedented temporal accuracy—independent of the atomic structure—with maximal photoemission at all kinetic energies given a wave packet with zero relative phase. Here, we perform numerical propagation of the timedependent Schrödinger equation and analytical calculations based on perturbation theory to show that the energyresolved maximal absorption of photons from the attosecond pulse does not uniquely occur at a zero relative phase of the initial wave packet. Instead, maximal absorption occurs at different relative wave packet phases, distributed as a nonmonotonous function with a smooth $$\pi /2$$ shift across the central photon energy (given a Fourierlimited Gaussian pulse). Similar results are also found in helium. Our finding is surprising, because it implies that the energyresolved photoelectrons are not mapped onetoone with the energyresolved absorbed photons of the attosecond pulse.
 Authors:

^{[1]}
;
^{[2]}
;
^{[3]}
 Lund Univ., Lund (Sweden); Stockholm Univ., Stockholm (Sweden)
 HarvardSmithsonian Center for Astrophysics, Cambridge, MA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
 Stockholm Univ., Stockholm (Sweden)
 Publication Date:
 Grant/Contract Number:
 AC0276SF00515; 20143724; 201603789
 Type:
 Accepted Manuscript
 Journal Name:
 Journal of Optics
 Additional Journal Information:
 Journal Volume: 19; Journal Issue: 11; Journal ID: ISSN 20408978
 Publisher:
 IOP Publishing
 Research Org:
 SLAC National Accelerator Lab., Menlo Park, CA (United States)
 Sponsoring Org:
 USDOE
 Country of Publication:
 United States
 Language:
 English
 Subject:
 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; attosecond; transient absorption; ATAS; pulse characterization; continuum transition
 OSTI Identifier:
 1410602
Dahlström, Jan Marcus, Pabst, Stefan, and Lindroth, Eva. Attosecond transient absorption of a bound wave packet coupled to a smooth continuum. United States: N. p.,
Web. doi:10.1088/20408986/aa8a93.
Dahlström, Jan Marcus, Pabst, Stefan, & Lindroth, Eva. Attosecond transient absorption of a bound wave packet coupled to a smooth continuum. United States. doi:10.1088/20408986/aa8a93.
Dahlström, Jan Marcus, Pabst, Stefan, and Lindroth, Eva. 2017.
"Attosecond transient absorption of a bound wave packet coupled to a smooth continuum". United States.
doi:10.1088/20408986/aa8a93. https://www.osti.gov/servlets/purl/1410602.
@article{osti_1410602,
title = {Attosecond transient absorption of a bound wave packet coupled to a smooth continuum},
author = {Dahlström, Jan Marcus and Pabst, Stefan and Lindroth, Eva},
abstractNote = {Here, we investigate the possibility of using transient absorption of a coherent bound electron wave packet in hydrogen as an attosecond pulse characterization technique. In a recent work, we have shown that photoionization of such a coherent bound electron wave packet opens up for pulse characterization with unprecedented temporal accuracy—independent of the atomic structure—with maximal photoemission at all kinetic energies given a wave packet with zero relative phase. Here, we perform numerical propagation of the timedependent Schrödinger equation and analytical calculations based on perturbation theory to show that the energyresolved maximal absorption of photons from the attosecond pulse does not uniquely occur at a zero relative phase of the initial wave packet. Instead, maximal absorption occurs at different relative wave packet phases, distributed as a nonmonotonous function with a smooth $\pi /2$ shift across the central photon energy (given a Fourierlimited Gaussian pulse). Similar results are also found in helium. Our finding is surprising, because it implies that the energyresolved photoelectrons are not mapped onetoone with the energyresolved absorbed photons of the attosecond pulse.},
doi = {10.1088/20408986/aa8a93},
journal = {Journal of Optics},
number = 11,
volume = 19,
place = {United States},
year = {2017},
month = {10}
}