title: Theoretical Evaluation of Terahertz Sources Generated From SnGa4Q7(Q=S, Se) as Infrared Nonlinear Optical Materials.
abstract: We theoretically evaluated the integrated knowledge that contributes to conversion efficiency, including the phonon, photon, and electron properties of infrared nonlinear optical materials such as SnGa4Q7(Q=S, Se), which are terahertz (THz) sources. Specifically, we developed a new formula to calculate the susceptibility of the difference frequency generation (DFG) optical process. By evaluating the characteristics of the materials themselves in the THz region, we found that a larger nonlinear susceptibility or a large figure of merit resulted in a large efficiency of the THz source by comparing the findings of SnGa4Se7and SnGa4S7under the same experimental conditions; furthermore, THz absorption was found to reduce the efficiency of the THz source for the two SnGa4Q7(Q=S, Se) materials. The efficiency of the THz source also depended on the experimental conditions. A large crystal size, strong pump intensity, and small THz wavelength resulted in better efficiency of the THz source based on the DFG process. The efficiency was found to be a comprehensive index to evaluate the THz source based on the DFG process.
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, No. 155, Yang Qiao Xi Road, Fuzhou, Fujian, China.
authors.forename: Wen-Dan
authors.initials: WD
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, No. 155, Yang Qiao Xi Road, Fuzhou, Fujian, China.
authors.forename: Chen-Sheng
authors.initials: CS
authors.lastname: Lin
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, No. 155, Yang Qiao Xi Road, Fuzhou, Fujian, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, No. 155, Yang Qiao Xi Road, Fuzhou, Fujian, China.
authors.forename: Yi-Zhi
authors.initials: YZ
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, No. 155, Yang Qiao Xi Road, Fuzhou, Fujian, China.
authors.forename: Guo-Liang
authors.initials: GL
authors.lastname: Chai
keywords: density functional calculations; difference frequency generation susceptibility; nonlinear optics; phonon frequency; wave conversion efficiency