Niobium oxide dichloride (NbOCl₂), a van der Waals crystal, exhibits exceptional second-harmonic generation (SHG) with high conversion efficiency, making it a promising candidate for on-chip quantum light sources, photon modulators, and sensors. To increase its suitability for integrated photonic systems, it is crucial to explore strategies for further improving optical nonlinear conversion efficiency. In this article, dielectric metasurfaces are employed to enhance SHG from patterned NbOCl₂ nanodisks. By precisely tuning their geometric parameters to achieve optical resonance near the excitation wavelength, a remarkable 25-fold enhancement in second-harmonic emission at 400 nm is achieved in nanodisks compared to the unpatterned thin film. The strong field enhancement within the NbOCl₂ nanodisks at nanophotonic resonances contributes to the observed increase in SHG. This work offers an effective strategy for boosting SHG in van der Waals NbOCl₂ thin films, paving the way for the development of efficient nonlinear optical components in integrated nanophotonics.

中文翻译：

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van der Waals NbOCl2 纳米片，用于增强二次谐波产生


氧化铌二氯化铌 （_{NbOCl 2}） 是一种范德华晶体，具有出色的二次谐波产生 （SHG） 和高转换效率，使其成为片上量子光源、光子调制器和传感器的有前途的候选者。为了提高其对集成光子系统的适用性，探索进一步提高光学非线性转换效率的策略至关重要。在本文中，采用介电超表面从图案化的_{NbOCl 2} 纳米片增强 SHG。通过精确调整它们的几何参数以实现激发波长附近的光学共振，与未图案化的薄膜相比，纳米盘在 400 nm 处的二次谐波发射显着提高了 25 倍。纳米光子共振时 NbOCl₂ 纳米片内的强场增强有助于观察到的 SHG 增加。这项工作为提高范德华_{NbOCl 2} 薄膜中的 SHG 提供了一种有效的策略，为集成纳米光子学中高效非线性光学元件的开发铺平了道路。