【摘要】 二次谐波效应和相位匹配能力对于二阶非线性光学晶体的实际应用至关重要.在本工作中,我们通过将具有立体化学活性电子对的Pb²⁺引入非相位匹配的Ga₂Se₃,增强其各向异性和二阶超极化率.基于以上策略,我们制备了一种硒化物PbGa₄Se₇,其晶体结构由类金刚石阴离子骨架和插入到间隙中的Pb²⁺组成.在1910 nm的激光照射下,PbGa₄Se₇具有大的二次谐波系数（3.3×AgGaS₂）;同时,其具有低的热膨胀系数各向异性（0.5）和合适的光学带隙（2.1 eV）,在2090 nm激光照射下,表现出高的激光诱导损伤阈值（7.0×AgGaS₂）.PbGa₄Se₇的相位匹配能力和强二次谐波效应可归因于非线性光学功能基元（四面体GaSe₄和金字塔PbSe₃结构单元）的协同作用产生了额外的各向异性和极化率.更多还原

【Abstract】 Strong second-harmonic generation（SHG） and phase-matchable capability at specific transmittance windows are crucial to the real application of nonlinear optical crystals.Herein,an efficient strategy of introducing Pb²⁺with stereochemically active lone-pair electrons into non-phase-matchable Ga₂Se₃ via enhancing the anisotropy microstructure is first applied to meet phase-matchable SHG intensity requirements,offering a selenide,namely,PbGa₄Se₇,which is designed and synthesized with a diamond-like anionic framework,where Pb²⁺cations reside in a parallel arrangement.As expected,PbGa₄Se₇ possesses a large SHG coefficient of 3.3times that of AgGaS₂ under the incident laser of 1910 nm.Moreover,PbGa₄Se₇ displays a high laser-induced damage threshold of 7.0 times that of AgGaS₂ at 2090 nm,which originates from the low anisotropy of thermal expansion coefficient（0.36） and suitable optical band gap（2.1 eV）.Theoretical calculations demonstrate that the considerable phase-matchable SHG response of PbGa₄Se₇ can be attributed to the synergies of tetrahedral GaSe₄ and pyramid PbSe₃microstructural blocks with additional anisotropy and polarizability.更多还原