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Theoretical Evaluation of Terahertz Sources Generated From SnGa 4 Q 7 (Q=S, Se) as Infrared Nonlinear Optical Materials
Author(s) -
Cheng WenDan,
Lin ChenSheng,
Zhang Hao,
Huang YiZhi,
Chai GuoLiang
Publication year - 2017
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201601128
Subject(s) - terahertz radiation , figure of merit , energy conversion efficiency , infrared , optoelectronics , optical rectification , photon , optics , wavelength , materials science , absorption (acoustics) , nonlinear optics , physics , laser
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 SnGa 4 Q 7 (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 SnGa 4 Se 7 and SnGa 4 S 7 under the same experimental conditions; furthermore, THz absorption was found to reduce the efficiency of the THz source for the two SnGa 4 Q 7 (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.