Momentum mapping of continuum-electron wave-packet interference

High harmonic generation via continuum wave-packet interference.

High-order harmonic generation (HHG) is investigated theoretically in the over-the-barrier ionization regime revealing the strong signature of interference between two separately ionized and separately propagating free wave packets of a single electron. The interference leads to the emission of coherent light at a photon energy corresponding to the kinetic-energy difference of the two recollidi...

Attosecond electron wave-packet interference observed by transient absorption.

We perform attosecond time-resolved transient absorption spectroscopy around the first ionization threshold of helium and observe rapid oscillations of the absorption of the individual harmonics as a function of time delay with respect to a superimposed, moderately strong infrared laser field. The phase relation between the absorption modulation of individual harmonics gives direct evidence for...

Attosecond electron wave packet interferometry

Probing the longitudinal momentum spread of the electron wave packet at the tunnel exit.

We present an ellipticity-resolved study of momentum distributions arising from strong-field ionization of helium. The influence of the ion potential on the departing electron is considered within a semiclassical model consisting of an initial tunneling step and subsequent classical propagation. We find that the momentum distribution can be explained by including the longitudinal momentum sprea...

Many-electron Wave Function and Momentum Density

Inelastic x-ray scattering at large momentum transfer is an ideal probe of the ground state of electrons in condensed matter. The experimental determination of the electron momentum density (EMD) is based on the Impulse Approximation (IA). In general, the EMD even in simple metals cannot be well represented by the mean-field Independent Particle Model (IPM). In other words, the many-electron wa...