Attosecond real-time observation of electron tunnelling in atoms

Abstract

Atoms exposed to intense light lose one or more electrons and become ions. In strong fields, the process is predicted to occur via tunnelling through the binding potential that is suppressed by the light field near the peaks of its oscillations. Here we report the real-time observation of this most elementary step in strong-field interactions: light-induced electron tunnelling. The process is found to deplete atomic bound states in sharp steps lasting several hundred attoseconds. This suggests a new technique, attosecond tunnelling, for probing short-lived, transient states of atoms or molecules with high temporal resolution. The utility of attosecond tunnelling is demonstrated by capturing multi-electron excitation (shake-up) and relaxation (cascaded Auger decay) processes with subfemtosecond resolution.

Attosecond control of collective electron motion in plasmas

“…On the one hand, ultrahigh light intensities provided by multi-terawatt femtosecond lasers can be used to drive collective electron motion in plasmas up to the 0.1-1 gigaelectronvolt energy range [1], opening the way to very compact laser-based particle accelerators for nuclear and medical applications [2]. On the other hand, controlled few-cycle light waves can be used at moderate intensities to drive and probe the attosecond dynamics of few-electron motion in atoms [3,4,5,6], molecules [7,8] and condensed matter [9,10] -with typical energies * These authors contributed equally to this work. …”

Time-diagnostics for improved dynamics experiments at XUV FELs

“…The relaxation pathways of the created vacancy via single (A1) and double (A2) Auger decay involving several intermediate states were directly observed by detecting 4d and two Auger electrons in coincidence [30]. Time constants for the Auger decay of τ A1 = 6.0 ± 0.7 fs and τ A2 = 30.8 ± 1.4 fs leading to Xe 2+ and Xe 3+ final states with two or three vacancies in the outer 5p shell, respectively, are known with high precision from time-domain studies [31] and energy-resolved measurements [32]. Averaged Xe 3+ and Xe 4+ ion yields (grey opened circles) as a function of the time delay are plotted in Figure 10 (Figure 10(c) and [31]).…”

“…Time constants for the Auger decay of τ A1 = 6.0 ± 0.7 fs and τ A2 = 30.8 ± 1.4 fs leading to Xe 2+ and Xe 3+ final states with two or three vacancies in the outer 5p shell, respectively, are known with high precision from time-domain studies [31] and energy-resolved measurements [32]. Averaged Xe 3+ and Xe 4+ ion yields (grey opened circles) as a function of the time delay are plotted in Figure 10 (Figure 10(c) and [31]). The electron dynamics leading to the transient Xe 4+ ion yield is governed by short-lived intermediate excited states (Figure 10(d) and τ A2 in [31]) leading to a fast decrease for positive time delays.…”

“…Averaged Xe 3+ and Xe 4+ ion yields (grey opened circles) as a function of the time delay are plotted in Figure 10 (Figure 10(c) and [31]). The electron dynamics leading to the transient Xe 4+ ion yield is governed by short-lived intermediate excited states (Figure 10(d) and τ A2 in [31]) leading to a fast decrease for positive time delays. Transient changes of the ion yields are observed within a noticeably broad time window (Figure 10(a) and (b)).…”

Carrier-envelope phase-dependent transmitted spectra in inversion-asymmetric media with permanent dipole moments

“…Ultrashort few-cycle laser pulses have a number of important applications, such as coherent control of ultrafast reaction, detection of atomic and molecular dynamics [2][3][4][5] and attosecond pulse generation [6][7][8][9][10][11]. Nonlinear optics with few-cycle pulses has many novel aspects.…”