M(Nh2so3)(2) (M=Sr, Ba): Two Deep-Ultraviolet Transparent Sulfamates Exhibiting Strong Second Harmonic Generation Responses And Moderate Birefringence

Over the last few decades, the development of each new nonlinear optical (NLO)-active functional unit has led to the discoveries of a series of excellent NLO materials. In the present work, based on first-principles studies, we identified a novel deep-UV (DUV) NLO-active functional unit, a non-pi-conjugated group viz. (NH2SO3)(-). By combining alkaline-earth metals with (NH2SO3)(-) group, two DUV transparent NLO sulfamates, M(NH2SO3)(2) (M=Sr, Ba) with superior optical properties including strong SHG responses (1.2 and 2.7 x KH2PO4 (KDP)), short UV cut-off edge (<190 nm) and moderate birefringence (0.056@589.3 nm for Sr(NH2SO3)(2)) were successfully synthesized. Our work has provided not only two promising DUV transparent NLO crystals, but also an innovative non-pi-conjugated unit for developing more DUV transparent NLO materials.