Nonlinear Optical Properties of Molecular Materials, Structures and Devices Thereof: A Theoretical Multi-Scale Approach

Building on our multi-scale workflow for simulations of linear optical properties of photonic devices embedding molecular materials[1], [2], we expanded the framework to nonlinear light-matter interactions based on molecular first hyperpolarizabilities <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\beta_{ijk}$</tex> [3]. This allows us to address properties such as second-harmonic generation (SHG)[3], [4] and its circular dichroism (CD). We simulate not only signal from the bulk of materials, but also at interfaces with vacuum[4] or with other materials. In there, the SHG signal within dipole approximation will also arise for centrosymmetric materials due to symmetry-breaking conditions at interfaces[4]. The crucial step for the bridging from quantum chemistry calculations to the device levels was construction of the hyper-transition-matrix <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{T}^{\text{Hyper}}$</tex> within Maxwell scattering theory[3] that links hyperpolarizabilities with scattered second-harmonic field: