Probing and manipulating the intriguing nonlinear optical responses in van der Waals (vdW) ferroelectrics offer opportunities for their applications in nanophotonics. Here, we report the observation of giant and tunable second-harmonic generation (SHG) in ferroelectric CuInP₂S₆ (CIPS) and CIPS/MoS₂ heterostructures. The results show that CIPS, ranging from multilayer to bulk-like samples, all exhibit strong SHG with giant anisotropy. The SHG anisotropy is attributed to the local strain along the a-axis that naturally exists in CIPS, as evidenced by piezoresponse force microscopy measurement. We further realized the strong modulation of SHG in CIPS by interfacing with monolayer MoS₂. A combination of polarization, temperature, and thickness-dependent SHG and photoluminescence analyses shows that the nonlinear optical signal control in CIPS/MoS₂ heterostructures is unrelated to the polar symmetry of CIPS and MoS₂ but is driven by light absorption-mediated interfacial coupling. Our study provides a material platform based on vdW ferroelectric heterostructures for achieving dynamic control of nonlinear optical responses, which shows great potential applications in modern nanophotonics.

中文翻译：

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通过与 MoS2 原子层接口对 CuInP2S6 中二次谐波产生的巨调制


探测和操纵范德华 （vdW） 铁电体中有趣的非线性光学响应为它们在纳米光子学中的应用提供了机会。在这里，我们报告了在铁电 CuInP₂S₆ （CIPS） 和 CIPS/MoS₂ 异质结构中观察到的巨型和可调二次谐波产生 （SHG）。结果表明，从多层样品到块状样品的 CIPS 都表现出强 SHG 和巨大的各向异性。SHG 各向异性归因于 CIPS 中自然存在的沿 a 轴的局部应变，压电响应力显微镜测量证明了这一点。通过与单层 MoS₂ 连接，我们进一步实现了 CIPS 中 SHG 的强调节。偏振、温度和厚度依赖性 SHG 和光致发光分析的组合表明，CIPS/MoS₂ 异质结构中的非线性光信号控制与 CIPS 和 MoS₂ 的极性对称性无关，而是由光吸收介导的界面耦合驱动的。我们的研究为实现非线性光学响应的动态控制提供了一种基于 vdW 铁电异质结构的材料平台，这在现代纳米光子学中显示出巨大的潜在应用。