Abstract Larger second-order harmonic generation (SHG) efficiency and high laser damage threshold (LDT) are two crucial requirements for the practical applications of IR nonlinear optical (NLO) materials. Li-(Ga, In)-Q2 (Q = S, Se) is a well-known IR NLO materials system, in which In Q bonds are more covalent than Ga Q bonds and benefit larger SHG efficiency. However, the incompatibility between LDT and SHG leads to a smaller LDT of LiInS2 than that of LiGaS2. A new IR NLO compound LiGa0.54In0.46S2 was successfully synthesized by the introduction of gallium in LiInS2, where mixing Ga3+ in In3+ sites result in a wider band-gap of 3.86 eV and a smaller thermal expansion anisotropy value (0.26) compared with LiInS2, leading to the large LDT of 12 times that of commercial AgGaS2 under 1064 nm at room temperature. Meanwhile, the title compound had a relatively strong SHG efficiency of about 0.6 times that of AgGaS2 under a 1910 nm laser radiation. This work highlights the strategy of pursuing IR NLO materials with high LDTs by atom doping in classic material systems.

中文翻译：

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LiGa0.54In0.46S2：一种新型大激光损伤阈值红外非线性光学材料，由LiInS2中的镓替代设计

摘要 较大的二次谐波产生（SHG）效率和高激光损伤阈值（LDT）是红外非线性光学（NLO）材料实际应用的两个关键要求。Li-(Ga, In)-Q2 (Q = S, Se) 是一种众所周知的 IR NLO 材料系统，其中 In Q 键比 Ga Q 键更共价，并有利于更高的 SHG 效率。然而，LDT 和 SHG 之间的不相容性导致 LiInS2 的 LDT 小于 LiGaS2 的 LDT。通过在 LiInS2 中引入镓，成功合成了一种新的 IR NLO 化合物 LiGa0.54In0.46S2，与 LiInS2 相比，在 In3+ 位点混合 Ga3+ 导致更宽的带隙 3.86 eV 和更小的热膨胀各向异性值 (0.26) ，导致室温下 1064 nm 下的大 LDT 是商业 AgGaS2 的 12 倍。同时，在 1910 nm 激光辐射下，标题化合物具有相对较强的 SHG 效率，约为 AgGaS2 的 0.6 倍。这项工作突出了通过在经典材料系统中进行原子掺杂来追求具有高 LDT 的 IR NLO 材料的策略。