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MM: Fachverband Metall- und Materialphysik

MM 34: Development of Calculation Methods

MM 34.2: Vortrag

Freitag, 21. März 2025, 10:30–10:45, H10

Sum frequency generation from real-time simulation in 2D crystals — •Mike Nico Pionteck¹, Myrta Grüning^2,3, Simone Sanna¹, and Claudio Attaccalite^3,4 — ¹Institut für Theoretische Physik and Center for Materials Research (LaMa), Justus-Liebig-Universität Gießen, Germany — ²School of Mathematics and Physics, Queen’s University Belfast, United Kingdom — ³European Theoretical Spectroscopy Facilities (ETSF) — ⁴CNRS/Aix-Marseille Université, Centre Interdisciplinaire de Nanoscience de Marseille UMR 7325 Campus de Luminy, France

Sum and difference frequency generation (SFG, DFG) are powerful experimental techniques which involve the interaction of two laser with frequency ω₁ and ω₂, generating an output beam with frequency ω=ω₁±ω₂ as second-order nonlinear response. These techniques are widely used to study 2D materials, providing complementary insights to those obtained from infrared and Raman spectroscopy.

We present an implementation of SFG and DFG within the Yambo code [1], based on real-time time-dependent adiabatic GW (TD-aGW). To account for local field effects and electron-hole interactions, our approach reduces to the Bethe-Salpeter equation (BSE) in the linear limit regime. We demonstrate this framework by calculating SFG and DFG signatures in h-BN and MoS₂. Furthermore, the method enables the extraction of higher-order response functions (e.g. TPA). This work establishes a first-principles approach to nonlinear optics, enabling investigations of optical responses of bulk materials with high versatility. [1] D. Sangalli et al., J. Phys. Condens. Matter 31, 325902 (2019).

Keywords: SFG and DFG; Nonlinear optics; Real-time simulation; TD-aGW; 2D materials