Separation of recollision mechanisms in nonsequential strong field double ionization of Ar: the role of excitation tunneling.
Vector momentum distributions of two electrons created in double ionization of Ar by 25 fs, 0.25 PW/cm(2) laser pulses at 795 nm have been measured using a "reaction microscope." At this intensity, where nonsequential ionization dominates, distinct correlation patterns are observed in the two-electron momentum distributions. A kinematical analysis of these spectra within the classical "recollision model" revealed an (e,2e)-like process and excitation with subsequent tunneling of the second electron as two different ionization mechanisms. This allows a qualitative separation of the two mechanisms demonstrating that excitation-tunneling is the dominant contribution to the total double ionization yield.
Feuerstein
B
B
Universität Freiburg, Hermann-Herder-Strasse 3, D-79104 Freiburg, Germany.
Moshammer
R
R
Fischer
D
D
Dorn
A
A
Schröter
C D
CD
Deipenwisch
J
J
Crespo Lopez-Urrutia
J R
JR
Höhr
C
C
Neumayer
P
P
Ullrich
J
J
Rottke
H
H
Trump
C
C
Wittmann
M
M
Korn
G
G
Sandner
W
W