Large Second Harmonic Generation and Birefringence from Extended Octupolar π-Conjugated Structures

The exploration of crystal materials for optical manipulation by nonlinear optical (NLO) and anisotropic light-matter interaction is of paramount importance in modern science and technology. However, in such crystal materials, finding the right balance between second harmonic generation (SHG), birefringence, and the bandgap presents a significant challenge. In this contribution, we employ extended octupolar π-conjugated groups devoid of intrinsic dipole moments to construct melonate-based inorganic-organic hybrid crystals, thereby achieving simultaneous large optical nonlinearity and anisotropy. In accordance with this strategy, Rb