Attosecond electron spectroscopy using a novel interferometric pump-probe technique.
We present an interferometric pump-probe technique for the characterization of attosecond electron wave packets (WPs) that uses a free WP as a reference to measure a bound WP. We demonstrate our method by exciting helium atoms using an attosecond pulse (AP) with a bandwidth centered near the ionization threshold, thus creating both a bound and a free WP simultaneously. After a variable delay, the bound WP is ionized by a few-cycle infrared laser precisely synchronized to the original AP. By measuring the delay-dependent photoelectron spectrum we obtain an interferogram that contains both quantum beats as well as multipath interference. Analysis of the interferogram allows us to determine the bound WP components with a spectral resolution much better than the inverse of the AP duration.
Mauritsson
J
J
Department of Physics, Lund Institute of Technology, P. O. Box 118, SE-221 00 Lund, Sweden.
Remetter
T
T
Swoboda
M
M
Klünder
K
K
L'Huillier
A
A
Schafer
K J
KJ
Ghafur
O
O
Kelkensberg
F
F
Siu
W
W
Johnsson
P
P
Vrakking
M J J
MJ
Znakovskaya
I
I
Uphues
T
T
Zherebtsov
S
S
Kling
M F
MF
Lépine
F
F
Benedetti
E
E
Ferrari
F
F
Sansone
G
G
Nisoli
M
M