The Effects of Geometry on the Hyperpolarizability

Abstract

Extensive studies in the past have focused on precise calculations of the nonlinear-optical susceptibility of thousands of molecules. In this work, we use the broader approach of considering how geometry and symmetry alone play a role. We investigate the nonlinear optical response of potential energy functions that are given by a superposition of force centers (representing the nuclear charges) that lie in various planar geometrical arrangements. We find that for certain specific geometries, such as an octupolar-like molecule with donors and acceptors of varying strengths at the branches, the hyperpolarizability is near the {\em fundamental limit}. In these cases, the molecule is observed to be well approximated by a three-level model - consistent with the three-level ansatz previously used to calculate the {\em fundamental limits}. However, when the hyperpolarizability is below the {\em apparent limit} (about a factor of thirty below the {\em fundamental limit}) the system is no longer representable by a three-level model; where both two-level and a many-state models are found to be appropriate, depending on the symmetry.

9 pages and 7 Figures

References in corpus (3)

• Compact Sum-Over-States Expression without Dipolar Terms for Calculating Nonlinear Susceptibilities
• Fundamental Limits of the Dispersion of the Two-Photon Absorption Cross-Section
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Cited by in corpus (11)

• Studies on optimizing potential energy functions for maximal intrinsic hyperpolarizability
• Monte Carlo Studies of the Fundamental Limits of the Intrinsic Hyperpolarizability
• The critical role of the energy spectrum in determining the nonlinear-optical response of a quantum system
• The influence of geometry and topology of quantum graphs on their nonlinear-optical properties
• Monte Carlo Studies of the Intrinsic Second Hyperpolarizability
• Geometry-Controlled Nonlinear Optical Response of Quantum Graphs
• The paradox of the many-state catastrophe of fundamental limits and the three-state conjecture
• Physics of the fundamental limits of nonlinear optics: A theoretical perspective
• A classical model of the upper bounds of the cascading contribution to the second hyperpolarizability
• Maximizing the hyperpolarizability of one-dimensional systems
• Three-state interactions determine the second-order nonlinear optical response