Quantum path control using attosecond pulse trains via UV-assisted resonance enhance ionization

Abstract

We theoretically investigate the quantum path selection in an ultraviolet (UV)-assisted near-infrared field with an UV energy below the ionization threshold. By calculating the ionization probability with different assistant UV frequencies, we find that a resonance-enhanced ionization peak emerges in the region Euv < Ip, where Euv is the photon energy and Ip is the ionization energy. With an attosecond pulse train (APT) centered in the resonance region, we show that the short quantum path can be well selected in the continuum case. By performing the electron trajectory analysis, we have further explained the physical mechanism of the quantum path selection. Moreover, we also demonstrate that in the resonance region, the harmonic emission from the selected paths is more efficient than that with the APT energy above the ionization threshold.

Attosecond transient absorption spectroscopy: Comparative study based on three-level modeling

“…In the last decade, attosecond technology has made great progresses which have offered much opportunities for the investigation of the time-resolved dynamics of electrons in atoms and molecules. [1][2][3] In general, an attosecond pulsed XUV light together with a synchronized infrared (IR) laser pulse is employed to shine on atoms or molecules, and then measure the photoions, photoelectrons, or the XUV photoabsorption spectrum. Especially, attosecond transient XUV absorption spectroscopy [4][5][6] explores a delay-dependent pumpprobe scheme to investigate ultrafast electron dynamics down to the subfemtosecond time scale, which provides very high precision control of the delay time between them.…”