LiNaB_6O_9F_2: A Promising UV NLO Crystal Having Fluorine-Directed Optimal Performances and Double Interpenetrating ~3B_6O_9F_2_∞ Networks

摘要

A long-lasting challenge in ultraviolet (UV) nonlinear optical (NLO) materialsdesign is to combine conflicting and harsh properties into one structure,including wide UV transparency, strong NLO efficiency, and moderate birefringenceto realize phase-matching at short wavelength. A fluorine-directedmaterial design strategy is adopted to accelerate the process of finding NLOmaterials with optimal performances. In this work, taking LiB_3O_5 (LBO) as amaternal structure, one O atom with two F atoms is substituted and LiNaB_6O_9F_2which possesses novel double interpenetrating ~3[B_6O_9F_2]∞ networksand fluorine-directed optimal performances including enhanced birefringenceand phase-matching capacity is successfully obtained. The perfect balanceamong deep-UV cutoff edge, large second-harmonic generation (SHG)response (1.1 × KDP), and moderate birefringence (0.067 at 1064 nm) ofLiNaB6O9F2 makes it a promising UV NLO crystal.