In order to explain the opposite phase matchability of two types of newly discovered chalcogenides, AX2MQ6 vs AX4M5Q12 belonging to the same R3 space group, the linear and nonlinear optical properties are calculated. ...In order to explain the opposite phase matchability of two types of newly discovered chalcogenides, AX2MQ6 vs AX4M5Q12 belonging to the same R3 space group, the linear and nonlinear optical properties are calculated. The calculated Electron Localization Function（ELF） show the acentricity of the bonds on the Q^2- ions with sp^3 hybridization is the main origin of the optical anisotropy. To quantify such an acentricity, a geometric parameter, the dihedral angle between the tetrahedral undersides and the xy-planes is defined. And the calculated birefringence depends on the above defined geometric parameter and the ion radius. This correlation reasonably explains the opposite phase matchability of two closely related chalcogenide families of AX2MQ6 and AX4M5Q12 and is shedding useful light on further exploration on phase matchable IR-NLO crystals.展开更多
基金supported by the National Natural Science Foundation of China(Nos.21233009,90922021,20773130,20733003,20803080,20973175)the“Knowledge Innovation Program of the Chinese Academy of Sciences”(KJCX2-YW-H20,CXJJ-11-M71)
文摘In order to explain the opposite phase matchability of two types of newly discovered chalcogenides, AX2MQ6 vs AX4M5Q12 belonging to the same R3 space group, the linear and nonlinear optical properties are calculated. The calculated Electron Localization Function（ELF） show the acentricity of the bonds on the Q^2- ions with sp^3 hybridization is the main origin of the optical anisotropy. To quantify such an acentricity, a geometric parameter, the dihedral angle between the tetrahedral undersides and the xy-planes is defined. And the calculated birefringence depends on the above defined geometric parameter and the ion radius. This correlation reasonably explains the opposite phase matchability of two closely related chalcogenide families of AX2MQ6 and AX4M5Q12 and is shedding useful light on further exploration on phase matchable IR-NLO crystals.
基金financially supported by the National Natural Science Foundation of China(21827813,21921001,22175172,22075283,92161125,and U21A20508)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2020303 and 2021300)。
