Sie befinden Sich nicht im Netzwerk der Universität Paderborn. Der Zugriff auf elektronische Ressourcen ist gegebenenfalls nur via VPN oder Shibboleth (DFN-AAI) möglich. mehr Informationen...
Time delays from one-photon transitions in the continuum
Ist Teil von
Optica, 2020-02, Vol.7 (2), p.154
Erscheinungsjahr
2020
Link zum Volltext
Quelle
Free E-Journal (出版社公開部分のみ)
Beschreibungen/Notizen
Attosecond photoionization time delays reveal information about the
potential energy landscape that an outgoing electron wavepacket probes
upon ionization. In this study, we experimentally quantify the
dependence of the time delay on the angular momentum of the liberated
photoelectrons. For this purpose, we resolved electron quantum-path
interference spectra in energy and angle using a two-color attosecond
pump–probe photoionization experiment in helium. A fitting procedure
of the angle-dependent interference pattern allows us to disentangle
the relative phase of all four quantum pathways that are known to
contribute to the final photoelectron signal. In particular, we
resolve the dependence on angular momentum of the delay of one-photon
transitions between continuum states, which is an essential and
universal contribution to the total photoionization delay observed in
attosecond pump–probe measurements. For such continuum–continuum
transitions, we measure a delay between outgoing
s
and
d
electrons as large as 12 attoseconds,
close to the ionization threshold in helium. Both
single-active-electron and first-principles
ab
initio
simulations confirm this observation for helium and
hydrogen, demonstrating the universality of the observed delays.