Strong second-harmonic generation (SHG) and a short ultraviolet (UV) cutoff edge are two crucial yet often conflicting parameters that must be finely tuned in the exploration of nonlinear optical (NLO) materials. In this study, two new rare earth borate NLO crystals, K₇BaSc₂B₁₅O₃₀ (KBSBO) and Rb₂₁Sr_3.8Sc_5.2B₄₅O₉₀ (RSSBO), were rationally designed through a bifunctional primitive strategy to achieve an optimized balance between favorable SHG efficiency and UV transparency. As anticipated, both KBSBO and RSSBO exhibit a wide UV transparency window below 190 nm. Notably, these tailored crystals display strong SHG responses, with RSSBO achieving a remarkable enhancement in SHG efficiency (2 × KDP), surpassing that of most deep-UV rare earth borates containing [B₅O₁₀] groups known to date. Theoretical calculations and structural analyses reveal that the impressive SHG activities primarily stem from the [B₅O₁₀] groups and [ScO₆] polyhedra. These findings suggest promising potential for KBSBO and RSSBO crystals as beryllium-free deep UV NLO materials.

中文翻译：

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双功能原始策略可增强含有 [B5O10] 基团的稀土硼酸盐的大量二次谐波产生和宽紫外透射率


强二次谐波产生（SHG）和短紫外（UV）截止边缘是两个至关重要但经常相互冲突的参数，在非线性光学（NLO）材料的探索中必须对其进行微调。在这项研究中，两种新型稀土硼酸盐NLO晶体，K ₇ BaSc ₂ B ₁₅ O ₃₀ (KBSBO) 和 Rb < b4> Sr _3.8 Sc _5.2 B ₄₅ O ₉₀ (RSSBO)，通过双功能原始策略合理设计以实现良好的倍频效率和紫外透明度之间的最佳平衡。正如预期的那样，KBSBO 和 RSSBO 均表现出 190 nm 以下的宽紫外透明窗口。值得注意的是，这些定制晶体表现出强烈的倍频响应，RSSBO 显着提高了倍频效率 (2 × KDP)，超过了大多数含有 [B ₅ O ₁₀ O ₁₀ ]基团和[ScO ₆ ]多面体。这些发现表明 KBSBO 和 RSSBO 晶体作为无铍深紫外 NLO 材料具有广阔的前景。