title: Fluorooxoborates: Beryllium-Free Deep-Ultraviolet Nonlinear Optical Materials without Layered Growth.
abstract: Deep-ultraviolet nonlinear optical (DUV NLO) crystals are the key materials to extend the output range of solid-state lasers to below 200 nm. The only practical material KBe2BO3F2suffers high toxicity through beryllium and strong layered growth. Herein, we propose a beryllium-free material design and synthesis strategy for DUV NLO materials. Introducing the (BO3F)4-, (BO2F2)3-, and (BOF3)2-groups in borates could break through the fixed 3D B-O network that would produce a larger birefringence without layering and simultaneously keep a short cutoff edge down to DUV. The theoretical and experimental studies on a series of fluorooxoborates confirm this strategy. Li2B6O9F2is identified as a DUV NLO material with a large second harmonic generation efficiency (0.9×KDP) and a large predicted birefringence (0.07) without layering. This study provides a feasible way to break down the DUV wall for NLO materials.
authors.affiliation: Key Laboratory of Functional, Materials and Devices for Special Environments of CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics & Chemistry of CAS, 40-1 South Beijing Road, Urumqi, 830011, China.
authors.forename: Bingbing
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Functional, Materials and Devices for Special Environments of CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics & Chemistry of CAS, 40-1 South Beijing Road, Urumqi, 830011, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Shi
authors.affiliation: Key Laboratory of Functional, Materials and Devices for Special Environments of CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics & Chemistry of CAS, 40-1 South Beijing Road, Urumqi, 830011, China.
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Key Laboratory of Functional, Materials and Devices for Special Environments of CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics & Chemistry of CAS, 40-1 South Beijing Road, Urumqi, 830011, China.
authors.forename: Fangfang
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Functional, Materials and Devices for Special Environments of CAS, Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics & Chemistry of CAS, 40-1 South Beijing Road, Urumqi, 830011, China.
authors.forename: Shilie
authors.initials: S
authors.lastname: Pan
keywords: boron; deep-ultraviolet; fluorooxoborates; nonlinear optical materials; second harmonic generation