Strong Field Quantum Path Control Using Attosecond Pulse Trains

Abstract

We show that attosecond pulse trains have a natural application in the control of strong field processes. In combination with an intense infrared laser field, the pulse train can be used to microscopically select a single quantum path contribution to a process that would otherwise consist of several interfering components. We present calculations that demonstrate this by manipulating the time-frequency properties of high order harmonics at the single atom level. This quantum path selection can also be used to define a high resolution attosecond clock.

Coherent Extreme Ultraviolet Light Amplification by Strong-Field-Enhanced Forward Scattering

“…In this Letter we consider the amplification of the XUV yield generated in high-harmonic generation (HHG) processes by considering the simultaneous excitation of He atoms with an intense IR driving pulse and an XUV pulse. It is known that synchronization of one or several low-order harmonics of high peak intensities with the driving IR laser pulse can produce a large yield enhancement [2,3]. The target medium is in this case strongly ionized due to the XUV photon energies that are considered and due to their high intensity, so that the influence of the combined fields on the HHG spectrum is at spectral regions of higher photon energies than the added XUV pulse.…”

Étude de la génération d'harmoniques anormales d'ordre élevé à basse intensité

“…Ce champ s'crit comme une somme des champsélectriques IR et harmoniques. Onécrit ce champélectrique total comme dans la référence [16], en ne considèrant aucun délai entre le champ IR et les harmoniques en phase. L'enveloppe des champs est trapèzoidale de durée 16 cycles du laser fondamental (correspondantà environ 50 fs).…”

High-Harmonic Generation

“…Isolated attosecond pulses have also been realized by other methods such as ionization shutter (Sekikawa et al, 2004) and polarization gate Sansone et al, 2006), and two-color scheme (Pfeifer et al, 2006) has also been proposed. The enhancement effect discussed in the preceding subsections provides a means to control HHG and new physical insights (Schafer et al, 2004;Ishikawa et al, 2009b). As an example, in this subsection, we present an alternative method of SAP generation using multi-cycle laser pulses, called attosecond enhancement gate for isolated pulse generation (AEGIS) .…”