ReBe2B5O11 (Re = Y, Gd)- A Series of Rare Earth Beryllium Borates as Deep-Ultraviolet Nonlinear Optical Materials

The rapid developments of the deep-ultraviolet (deep-UV) laser science and technology urgently demand the nonlinear optical crystals which have large band gap enough to transmit the deep-UV light. Herein, we synthesized a series of new rare earth beryllium borates: ReBe2B5O11 (Re = Y, Gd). The structures of all these materials, for both alpha and beta phases, are featured by a novel platelike infinite superlayer [Be2B5O11]3-. Each [Be2B5O11]3- layer is further connected to the neighbor superlayer through Re3+ cations coordinating with O atoms. The beta-ReBe2B5O11 (Re=Y, Gd) have relatively large nonlinear optical coefficients and short UV cut-off wavelength below 200nm. Our investigations indicate that they are promising deep-UV NLO crystals.