PT  - JOURNAL ARTICLE
AU  - Villeneuve, D. M.
AU  - Hockett, Paul
AU  - Vrakking, M. J. J.
AU  - Niikura, Hiromichi
TI  - Coherent imaging of an attosecond electron wave packet
AID  - 10.1126/science.aam8393
DP  - 2017 Jun 16
TA  - Science
PG  - 1150--1153
VI  - 356
IP  - 6343
4099  - http://science.sciencemag.org/content/356/6343/1150.short
4100  - http://science.sciencemag.org/content/356/6343/1150.full
SO  - Science2017 Jun 16; 356
AB  - When a burst of light ejects an electron from an atom, the later detection of two charged particles masks a great deal of intermittent quantum mechanical complexity. Villeneuve et al. provide a striking look at the wavelike properties of the electron just as it emerges from neon, expelled by two photons from an attosecond pulse train in a strong infrared field. The phase distribution displays the characteristic three-node structure of an f-wave, which the Stark shift from the strong field appears to select with a single magnetic quantum number of 0.Science, this issue p. 1150Electrons detached from atoms or molecules by photoionization carry information about the quantum state from which they originate, as well as the continuum states into which they are released. Generally, the photoelectron momentum distribution is composed of a coherent sum of angular momentum components, each with an amplitude and phase. Here we show, by using photoionization of neon, that a train of attosecond pulses synchronized with an infrared laser field can be used to disentangle these angular momentum components. Two-color, two-photon ionization via a Stark-shifted intermediate state creates an almost pure f-wave with a magnetic quantum number of zero. Interference of the f-wave with a spherically symmetric s-wave provides a holographic reference that enables phase-resolved imaging of the f-wave.