Observation of laser-induced electronic structure in oriented polyatomic molecules.
All attosecond time-resolved measurements have so far relied on the use of intense near-infrared laser pulses. In particular, attosecond streaking, laser-induced electron diffraction and high-harmonic generation all make use of non-perturbative light-matter interactions. Remarkably, the effect of the strong laser field on the studied sample has often been neglected in previous studies. Here we use high-harmonic spectroscopy to measure laser-induced modifications of the electronic structure of molecules. We study high-harmonic spectra of spatially oriented CH3F and CH3Br as generic examples of polar polyatomic molecules. We accurately measure intensity ratios of even and odd-harmonic orders, and of the emission from aligned and unaligned molecules. We show that these robust observables reveal a substantial modification of the molecular electronic structure by the external laser field. Our insights offer new challenges and opportunities for a range of emerging strong-field attosecond spectroscopies.
Laboratorium für Physikalische Chemie, ETH Zürich, 8093 Zürich, Switzerland.
P M
PM
Kraus
Moscow Institute of Physics and Technology, Dolgoprudny 141700, Russia.
O I
OI
Tolstikhin
Laboratorium für Physikalische Chemie, ETH Zürich, 8093 Zürich, Switzerland.
D
D
Baykusheva
Laboratorium für Physikalische Chemie, ETH Zürich, 8093 Zürich, Switzerland.
A
A
Rupenyan
Laboratorium für Physikalische Chemie, ETH Zürich, 8093 Zürich, Switzerland.
J
J
Schneider
FOSS Analytical A/S, FOSS Allé 1, Hillerød DK-3400, Denmark.
C Z
CZ
Bisgaard
Department of Engineering Science, The University of Electro-Communications, 1-5-1 Chofu-ga-oka,Chofu-shi, Tokyo 182-8585, Japan.
T
T
Morishita
Department of Chemistry, Aarhus University, Aarhus C 8000, Denmark.
F
F
Jensen
Department of Physics and Astronomy, Aarhus University, Aarhus C 8000, Denmark.
L B
LB
Madsen
Laboratorium für Physikalische Chemie, ETH Zürich, 8093 Zürich, Switzerland.
H J
HJ
Wörner