Mainz 2017 – scientific programme

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A: Fachverband Atomphysik

A 26: Poster Session II

A 26.32: Poster

Wednesday, March 8, 2017, 17:00–19:00, P OG1

Robust enhancement of high harmonic generation via attosecond control of ionization — Barry D. Bruner, •Michael Krüger, Oren Pedatzur, Doron Azoury, Gal Orenstein, and Nirit Dudovich — Weizmann Institute of Science, 76100 Rehovot, Israel

Advancements in high harmonic generation (HHG) have led to the development of table-top XUV and soft x-ray light sources for attosecond science. However, the very low conversion efficiency from the strong driving laser fields to short wavelength HHG light poses a significant practical limitation for the use of these sources in experimental applications. We show that a two colour driving field produces a considerable enhancement of the ionization rate compared to that of a single colour field, leading to huge increases in the HHG efficiency. We use a tunable mid-IR (1300-1600 nm) source as a driving field and a weaker 800 nm beam as an assisting field. By systematically varying the field parameters we can observe increases in HHG efficiency of over two orders of magnitude. The enhancement is achieved via sub-cycle control of the tunnel ionization dynamics in the bichromatic driving field. Most schemes for increasing the HHG efficiency rely on phase matching and involve careful control of a large number of experimental parameters. However, our scheme is robust to phase matching effects and requires control of just a single parameter, namely the ionization rate. The robustness of this approach makes great strides toward improving the simplicity and practicality of high flux HHG sources.