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DS: Dünne Schichten

DS 24: Postersitzung II

DS 24.1: Poster

Dienstag, 8. März 2005, 17:00–19:00, Poster TU B

Nonlinear optical coefficients from first-principles calculations: Different numerical approaches — •Roman Leitsmann, W.G. Schmidt, P.H. Hahn und F. Bechstedt — Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany

Different numerical and methodological approaches for the ab initio calculations of the nonlinear optical response are used in the literature[1,2]. On the one hand, the formulas used are not easily seen to be equivalent. On the other hand, the numerical results even for well characterized bulk systems like GaAs do neither agree well with each other nor with experiment[3]. We revisit the derivation of the relevant expressions for the second harmonic generation (SHG) and show analytically the equivalence of the approaches[1,2] within the independent-particle approximation. In addition, we develope an approach to include excitonic effects in the SHG spectra over a wide energy range. Numerical results for bulk GaAs are presented which show the large influence of technical parameters on the final results.

[1] J.L.P. Hughes and J.E. Sipe, Phys. Rev. B 53, 10751 (1996).

[2] B. Adolph and F. Bechstedt, Phys. Rev. B 57, 6519 (1998).

[3] S. Bergfeld and W. Daum, Phys. Rev. Lett. 90, 036801 (2003).