Beryllium-Free β-Rb2 Al2 B2 O7 as a Possible Deep-Ultraviolet Nonlinear Optical Material Replacement for KBe2 BO3 F2.

A new beryllium-free deep-ultraviolet (DUV) nonlinear optical (NLO) material, β-Rb2 Al2 B2 O7 (β-RABO), has been synthesized and characterized. The chiral nonpolar acentric material shows second-harmonic generation (SHG) activity at both 1064 and 532 nm with efficiencies of 2×KH2 PO4 and 0.4×β-BaB2 O4 , respectively, and exhibits a short absorption edge below 200 nm. β-Rb2 Al2 B2 O7 has a three-dimensional structure of corner-shared Al(BO3 )3 O polyhedra. The discovery of β-RABO shows that through careful synthesis and characterization, replacement of KBe2 BO3 F2 (KBBF) by a Be-free DUV NLO material is possible.