A2BeS2O8(A = NH4, K, Rb, Cs) Deep Ultraviolet Nonlinear OpticalCrystals

A series of new noncentrosymmetric beryllium sulfates,A2BeS2O8(A = NH4, K, Rb, Cs), were rationally designed and synthesizedbased on the parent borophosphates KMBP2O8(M = Sr, Ba). Owing tothe rigid three-dimensional frameworks, A2BeS2O8(A = NH4, K, Rb, Cs)showed the high thermodynamic stabilities. Among them, A2BeS2O8(A =K, Rb, Cs) exhibited the highest thermodynamic stabilities among all thereported nonlinear (NLO) sulfates. In addition, benefiting from theflexibleBe-O bonds within [BeO4], A2BeS2O8(A = NH4, K, Rb, Cs) exhibitedthe enhanced second harmonic generation (SHG) responses, which wereabout 3 to 5 times that of parent borophosphates. Furthermore, theypossessed a moderate birefringence of 0.013-0.024 and could betransparent down to the deep ultraviolet (DUV) region below 200 nm.This work indicated that the basic building blocks in borophosphates and beryllium sulfates were potentially interchangeable, whichprovided the possibility for a further study of new NLO crystals.

Automated summary

A series of new noncentrosymmetric beryllium sulfates were designed and synthesized based on the parent borophosphates. They showed high thermodynamic stabilities and enhanced second harmonic generation (SHG) responses. They also exhibited moderate birefringence and transparency in the deep ultraviolet (DUV) region.