Enhancement of high-order harmonic generation at tuned wavelengths through adaptive control.
An adaptive learning loop enhances the efficiency and tuning of high-order harmonic generation. In comparison with simple chirp tuning, we observe a broader tuning range and a twofold to threefold enhancement in integrated photon flux in the cutoff region. The driving pulse temporal phase varies significantly for different tunings and is more complicated than a simple chirp. We compare our experimental results with a one-dimensional, time-dependent model that incorporates the intrinsic atomic response, the experimental pulse temporal phase, ionization effects, and transverse coherence of the spatial mode of the laser. The model agrees with our experimental results and indicates that a specific quantum path coupled with ionization effects determines the optimized harmonic spectrum.
Reitze
David H
DH
Laboratoire d'Optique Appliquée, Ecole Nationale Supérieure des Techniques Avancées, Ecole Polytechnique, Centre National de la Recherche Scientifique, Unité Mixte de Recherche (UMR 7639), 91761 Palaiseau Cedex, France. reitze@phys.ufl.edu
Kazamias
Sophie
S
Weihe
Frederick
F
Mullot
Geneviève
G
Douillet
Denis
D
Augé
Frederika
F
Albert
Olivier
O
Ramanathan
Vidya
V
Chambaret
Jean Paul
JP
Hulin
Danièle
D
Balcou
Philippe
P