Stuttgart 2012 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 44: Attosecond physics II

A 44.6: Vortrag

Freitag, 16. März 2012, 12:00–12:15, V57.05

Enhanced High-Order Harmonic Generation using dual gas targets — •Christoph M. Heyl, Fernando Brizuela, Piotr Rudawski, Cord Arnold, and Anne L’Huillier — Department of Physics, Lund University, P. O. Box 118, SE-22100 Lund, Sweden

High-order harmonic generation (HHG) in gases is nowadays well established and used for a variety of applications, in particular for the generation of attosecond pulses which give access to ultrafast phenomena in various fields of physics. This highly nonlinear light conversion process suffers, however, from a relatively low conversion efficiency. Several techniques have been implemented in order to enhance the efficiency, based on either improving phase matching or enhancing the single atom response. In this work, we investigate the possibilities of using a dual gas target in order to enhance the single atom response in the second target by driving the HHG process with an intense laser field and a superimposed harmonic field, generated in the first target. We demonstrate a significant enhancement of the harmonic signal (up to an order of magnitude), if an argon cell is placed in front of our low pressure neon cell. A similar effect has been observed earlier [1,2] involving an interpretation focusing on the role of the high-order harmonic field for controlling the ionization process in the second target. Our experimental results indicate that the enhancement happens due to low order harmonics which are efficiently generated in the first target.

[1] K. Ishikawa et al., Phys. Rev. Lett. 91, 043002 (2003)
[2] A. Heinrich et al., J. Phys. B. 39, S275 (2006)