Tracking attosecond electronic coherences using phase-manipulated extreme ultraviolet pulses

Abstract

The recent development of novel extreme ultraviolet (XUV) coherent light sources bears great potential for a better understanding of the structure and dynamics of matter 1,2 . Promising routes are advanced coherent control and nonlinear spectroscopy schemes in the XUV energy range, yielding unprecedented spatial and temporal resolution 3,4 . However, their implementation has been hampered by the experimental challenge of generating XUV pulse sequences with precisely controlled timing and phase properties. In particular, direct control and manipulation of the phase of individual pulses within a XUV pulse sequence opens exciting new possibilities for coherent control and multidimensional spectroscopy 4 , but has

Nonlinear ionization dynamics of hot dense plasma observed in a laser-plasma amplifier

“…quantum computing 27 , where the ultrashort time-domain shaped pulses can be used for preparing the ion states of ultracold ions, fixed in optical lattices, and for switching between resonant core transitions, as the pulses are highly stable due to the fixed transition dipole moment. Furthermore, it opens up the possibility of tracking electronic 28 and molecular 29 dynamics in pump-probe experiments, where the controllable time-domain properties of the XUV pulse result in highly adaptable probe beams. Additionally, one could envision using the tuneable time-domain XUV pulse sequence as an exquisite source for XUV coherent spectroscopies.…”

High-gain harmonic generation with temporally overlapping seed pulses and application to ultrafast spectroscopy

“…The pulse pair propagates to the modulator section of the FEL, where it seeds the n th -order HGHG process (n = 5, 6 in this work). In the regime of temporally well-separated seed pulses (τ ≥ 1.5∆t = 150 fs), we obtain a clean XUV pulse pair at the n th harmonic with very precise delay τ and relative phase nφ 21 [15]. In this case, an upper delay limit τ ≤ 1.3 ps is given by the finite length of the electron bunch used for HGHG.…”

“…More details about the technique and its extension to the XUV regime can be found in Refs. [15,17], and [25]. A phase-locked XUV pulse pair is created by twin-pulse seeding of the HGHG process at FERMI [see Fig.…”

“…Note that here t represents the laboratory time frame. This leads to a nΩ 21 t-modulation of the relative phase of the n th order FEL harmonic [15] and consequently to a modulation in the WPI signal in the laboratory time frame:…”

“…We have recently implemented a phase-modulation technique for XUV pulses, which, for the first time, simultaneously achieved phase-locking and strong background suppression due to lock-in detection [15]. This allowed us to follow the coherent evolution of XUV wave packets with high time resolution and sensitivity.…”