Optimization of Quantum Trajectories Driven by Strong-Field Waveforms

Stefan Haessler (1) , T Balčiunas (1) , G Fan (1) , G Andriukaitis (1) , A Pugžlys (1) , A Baltuška (1) , T Witting (2) , R Squibb (2) , A Zaïr (1) , J W G Tisch (2) , J P Marangos (2) , L Chipperfield (3)

1 TU Wien - Vienna University of Technology = Technische Universität Wien
2 Imperial College London
3 MBI - Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie

Quasi-free field-driven electron trajectories are a key element of strong-field dynamics. Upon recollision with the parent ion, the energy transferred from the field to the electron may be released as attosecond-duration XUV emission in the process of high harmonic generation (HHG). The conventional sinusoidal driver fields set limitations on the maximum value of this energy transfer and the efficient return of the launched electron trajectories. It has been predicted that these limits can be significantly exceeded by an appropriately ramped-up cycle-shape [L. Chipperfield et al., Phys. Rev. Lett. 102, 063003 (2009)]. Here, we present an experimental realization of similar cycle-shaped waveforms and demonstrate control of the HHG process on the single-atom quantum level via attosecond steering of the electron trajectories. With our improved optical cycles, we boost the field-ionization launching the electron trajectories, increase the subsequent field-to-electron energy transfer, and reduce the trajectory duration. We demonstrate, in realistic experimental conditions, two orders of magnitude enhancement of the generated XUV flux together with an increased spectra extension. This application, which is only one example of what can be achieved with cycle-shaped high-field light-waves, has significant implications for attosecond spectroscopy and molecular self-probing.

Domaines: Physique [physics]

Stefan Haessler, T Balčiunas, G Fan, G Andriukaitis, A Pugžlys, et al.. Optimization of Quantum Trajectories Driven by Strong-Field Waveforms. Physical Review X, 2014, 4, pp.021028. ⟨10.1103/PhysRevX.4.021028⟩. ⟨hal-01071424v2⟩