Wang Jingyu, Yang Weimin, He Yonglin
School of Physics and Information Engineering, Shanxi Normal University, Taiyuan 030000, China.
School of Electronic Information, Zhangzhou Institute of Technology, Zhangzhou 363000, China.
J Chem Phys. 2025 May 7;162(17). doi: 10.1063/5.0263451.
Circular dichroism (CD) spectroscopy represents a crucial technique for probing the structural details of chiral molecules. In recent years, emerging chiral metasurfaces have emerged as a promising platform by generating localized, intense chiral fields. Nevertheless, current metasurfaces predominantly function within the visible and near-infrared spectra with limited response in the ultraviolet (UV) spectrum due to materials and fabrication challenges. In this study, we report the attainment of a remarkably high Q factor of 1200, concomitant with a relatively pronounced planar chirality with a CD value of 0.67 under normal incidence in chiral all-dielectric Ta2O5 metasurfaces in the near-UV region. This achievement is realized through the strong coupling between magnetic dipole resonances and Mie surface lattice resonances, which occurs when the two resonance modes are both spatially and spectrally coincident. Our findings not only chart a novel trajectory for the realization of high-performance chiral metasurfaces in the UV region but also hold substantial potential for diverse chiral nanophotonic applications, such as sensing, lasing, and nonlinear optics investigations.
圆二色性（CD）光谱是探测手性分子结构细节的关键技术。近年来，新兴的手性超表面通过产生局域化的强手性场，成为一个很有前景的平台。然而，由于材料和制造方面的挑战，目前的超表面主要在可见光和近红外光谱范围内起作用，在紫外（UV）光谱中的响应有限。在本研究中，我们报道了在手性全介质Ta2O5超表面的近紫外区域，实现了高达1200的显著高Q因子，同时在正常入射下具有相对明显的平面手性，CD值为0.67。这一成果是通过磁偶极子共振与米氏表面晶格共振之间的强耦合实现的，当这两种共振模式在空间和光谱上都重合时就会发生这种耦合。我们的研究结果不仅为在紫外区域实现高性能手性超表面开辟了一条新途径，而且在传感、激光和非线性光学研究等多种手性纳米光子应用中具有巨大潜力。
