Open AccessHigh harmonic generation-2ω attosecond stereo-photoionization interferometry in N2
Author(s) -
V. Loriot,
A. Marciniak,
Saikat Nandi,
G. Karras,
Marius Hervé,
Éric Constant,
Étienne Plésiat,
Alicia Palacios,
Fernando Martín,
F. Lépine
Publication year - 2020
Publication title -
jphys photonics
Language(s) - English
Resource type - Journals
ISSN - 2515-7647
DOI - 10.1088/2515-7647/ab7b10
Subject(s) - photoionization , attosecond , extreme ultraviolet , high harmonic generation , physics , atomic physics , interferometry , ionization , photon energy , femtosecond , harmonic spectrum , photon , photoionization mode , photoemission spectroscopy , spectroscopy , optics , laser , ultrashort pulse , x ray photoelectron spectroscopy , ion , nuclear magnetic resonance , quantum mechanics
We have investigated photoionization delays in N 2 by combining an extreme ultraviolet (XUV) attosecond pulse train generated by high harmonic generation (HHG) and a second harmonic femtosecond pulse with angularly resolved photoelectron spectroscopy. While photoionization delay measurements are usually performed by using a standard XUV-infrared scheme, here we show that the present approach allows us to separate electronic states that otherwise would overlap, thus avoiding the spectral congestion found in most molecules. We have found a relative delay between the X and A ionic molecular states as a function of the photon energy of up to 40 attoseconds, which is due to the presence of a shape resonance in the X channel. This approach can be applied to other small quantum systems with few active electronic states.