Dimensionality Engineering of Fluorozirconium Phosphates for Deep-UV-Transparent Crystals with Enhanced Second-Harmonic Generation and Birefringence

). These compounds exhibit clear dimension-dependent optical properties, with reduced dimensionality leading to enhanced SHG responses and larger birefringence. Notably, the fluorine-rich 1D compounds display the strongest SHG efficiency (up to 2.1 × KDP) and the largest birefringence (0.053 @ 550 nm) within the series. Structure-property analyses reveal that decreasing the structural dimensionality promotes increased local distortion of Zr-centered polyhedra and more uniform dipole alignment, thereby amplifying both SHG and birefringence. This work establishes dimensionality engineering of fluorozirconium phosphates as an effective strategy for fine-tuning key optical properties while maintaining deep-UV transparency.