Na2ZnGe2S6: A New Infrared Nonlinear Optical Material with Good Balance between Large Second-Harmonic Generation Response and High Laser Damage Threshold

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• 作者：Guangmao Li ; Kui Wu ; Qiong Liu ; Zhihua Yang ; Shilie Pan
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：June 15, 2016
• 年：2016
• 卷：138
• 期：23
• 页码：7422-7428
• 全文大小：548K
• 年卷期：0
• ISSN：1520-5126

文摘

The development of frequency-conversion technology in the infrared region is in urgent need of new excellent infrared nonlinear optical (IR NLO) materials. How to achieve a good balance between laser damage threshold (LDT) and NLO coefficient (d_ij) for new IR NLO candidates is still a challenge. The combination of the highly electropositive alkali metal (Na) and Zn with d¹⁰ electronic configuration into crystal structure affords one new IR NLO material, Na₂ZnGe₂S₆. It exhibits excellent properties including a wide transparent region (0.38–22 μm), large band gap (3.25 eV), and especially a balance between a strong NLO coefficient (30-fold that of KDP) and a high LDT (6-fold that of AgGaS₂), indicating a promising application in the IR region. Moreover, novel common-vertex-linked wavelike _∞[GeS₃]_n chains are interestingly discovered in Na₂ZnGe₂S₆, which rarely exist in the reported thiogermanides containing alkali metals. In addition, calculated SHG density and dipole moment demonstrate that the large NLO response is mainly attributed to the cooperative effects of the [GeS₄] and [ZnS₄] units.