KAg_(3)Ga_(8)S_(14):一种高激光损伤阈值的中远红外非线性光学材料  

KAg_(3)Ga_(8)S_(14):An Mid-and Far-infrared Nonlinear Optical Material Exhibiting High Laser-induced Damage Threshold

作　　者：赵锦旭 张铭枢 陈文发 姜小明[1] 刘彬文 郭国聪[1] Zhao Jinxu;Zhang Mingshu;Chen Wenfa;Jiang Xiaoming;Liu Binwen;Guo Guocong(State Key Laboratory of Structural Chemistry,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences,Fuzhou 350002,China;School of Physical Science and Technology,ShanghaiTech University,Shanghai 201210,China)

机构地区：[1]中国科学院福建物质结构研究所结构化学国家重点实验室,福州350002 [2]上海科技大学物质科学与技术学院,上海201210

出　　处：《化学学报》2022年第3期259-264,共6页Acta Chimica Sinica

基　　金：国家自然科学基金(Nos.22075283,92161125);中国科学院青年创新促进会(No.2021300)资助。

摘　　要：兼具大的非线性光学(NLO)效应和高的激光损伤阈值(LIDT)是中远红外NLO材料领域最具挑战性的问题之一.这里,将碱金属离子K^(+)引入到以黄铜矿AgGaS_(2)为基底的材料中,获得硫属化合物KAg_(3)Ga_(8)S_(14).它的晶体结构采用与黄铜矿相类似的三维蜂窝状开放框架,其中畸变四面体GaS_(4)和AgS_(4)以高度定向的方式排列,产生中等的倍频效应(0.4×AgGaS_(2)@1910 nm).值得注意的是,通过拓宽带隙(2.95 eV),该化合物拥有高的激光损伤阈值(4.6×AgGaS_(2)@1064 nm).此外,通过理论计算表明四面体GaS_(4)和AgS_(4)决定硫属化合物KAg_(3)Ga_(8)S_(14)的NLO光学性质.Nonlinear optical(NLO)crystals can produce tunable lasers due to their second-harmonic generation,sum-frequency generation,difference-frequency generation and optical parametric oscillation.The famous oxide-based NLO materials such as KH2PO4(KDP),β-BaB2O4(BBO)and LiB3O5(LBO)are widely used in ultraviolet-visible(UV-Vis)re-gion.Nevertheless,they are not suitable for the mid-and far-infrared region because of the strong absorption there.Currently,commercially available IR NLO materials are rare,such as chalcogenides AgGaS_(2)(AGS),AgGaSe_(2)and phosphorus ZnGeP2,which have the advantages of large NLO coefficient and wide transmission range,but they have drawbacks,like low laser-induced damage threshold(LIDT).Discovering NLO crystals that exhibit simultaneously large NLO and high LIDT is a huge challenge.Here,the introducing electropositive alkali metal ionic K+in chalcopyrite AGS successfully affords a new sulfide KAg_(3)Ga_(8)S_(14)by high temperature solid state reaction.Its crystal structure adopts a three-dimensional honeycomb-like open framework,in which all tetrahedral AgS_(4)and GaS_(4)units are arranged in a highly oriented manner,thereby producing about a medium phase-matching second harmonic generation(SHG)response of 0.4 times that of the benchmark AGS at the incident laser of 1910 nm.Remarkably,the compound possesses a wide band gap(2.95 eV),thus avoiding two-photon absorption of the incident 1064 nm laser,and exhibits a high LIDT of 4.6 times that of the AGS at the laser of 1064 nm.Moreover,KAg_(3)Ga_(8)S_(14)has a wide transmission range(0.25—25.0μm)that covers the two important atmospheric windows of 3—5 and 8—12μm.Furthermore,according to theoretical calculations,the conductive band is mostly composed of Ga-4s and S-3p states,mixing with small amounts of Ga-4p state,whereas the valence band near the Fermi level originates predominately from Ag-4p and S-3p states,mixing with small amounts of Ga-4p state,indicating that tetrahedral GaS_(4)and AgS_(4)units gov-ern the optical and NLO propertie

关 键 词：硫属化合物 非线性光学 倍频效应 激光损伤阈值 晶体结构 

分 类 号：O437[机械工程—光学工程] TN249[理学—光学] TB34[理学—物理]