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A: Fachverband Atomphysik

A 25: Attosecond physics

A 25.8: Poster

Mittwoch, 13. März 2019, 16:15–18:15, S Fobau Physik

Effective Nonlinearity of Ionization Harmonics in Amorphous Solids — •Benjamin Liewehr¹, Björn Kruse¹, Christian Peltz¹, Peter Jürgens², Anton Husakou², Mikhail Ivanov², Marc Vrakking², Alexandre Mermillod-Blondin², and Thomas Fennel^1,2 — ¹Institut für Physik, Universität Rostock, Albert-Einstein-Str. 23, D-18051 Rostock — ²Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Str. 2A, D-12489 Berlin

The notion of nonlinear optical phenomena in dielectric solids has been recently complemented by the physics of high-harmonic generation (HHG) [1], associated with interband recombination and Bloch oscillations in strong laser fields [2]. This picture, however, fails to explain recent measurements of the harmonic emission close to the damage threshold of amorphous wide-bandgap materials, as the sub-femtosecond ejection dynamics of electrons has not been included so far. Using a rate equation based ionization-radiation model we show that the ionization current as well as the Brunel mechanism, known from gases [3], are also potential sources of low order harmonics in solids. We present an approach to discriminate the harmonics from ionization and Kerr-type contributions, by adapting the concept of nonlinear wave mixing and determine an effective nonlinearity order of the generating process.

[1] H. Liu et al., Nature Phys. 13, 262 (2017)

[2] G. Vampa, et al. Nature 522, 462 (2015)

[3] F. Brunel, J. Opt. Soc. Am. B 4, 521 (1990)