M(NH2SO3)2 (M=Sr, Ba): Two Deep‐Ultraviolet Transparent Sulfamates Exhibiting Strong Second Harmonic Generation Responses and Moderate Birefringence

Abstract 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‐π‐conjugated group viz. (NH 2 SO 3 ) − . By combining alkaline‐earth metals with (NH 2 SO 3 ) − group, two DUV transparent NLO sulfamates, M(NH 2 SO 3 ) 2 (M=Sr, Ba) with superior optical properties including strong SHG responses (1.2 and 2.7 × KH 2 PO 4 (KDP)), short UV cut‐off edge (<190 nm) and moderate birefringence (0.056@589.3 nm for Sr(NH 2 SO 3 ) 2 ) were successfully synthesized. Our work has provided not only two promising DUV transparent NLO crystals, but also an innovative non‐π‐conjugated unit for developing more DUV transparent NLO materials.