Near-Ultraviolet Dielectric Metasurfaces: from Surface-Enhanced Circular Dichroism Spectroscopy to Polarization-Preserving Mirrors
Near-Ultraviolet Dielectric Metasurfaces: from Surface-Enhanced Circular Dichroism Spectroscopy to Polarization-Preserving Mirrors
复制标题
DOI：
10.1021/acs.jpcc.8b11245
复制
发表时间：
2019-03
期刊：
影响因子：
--
通讯作者：
Kan Yao;Yuebing Zheng
中科院分区：
文献类型：
--
作者：
Kan Yao;Yuebing Zheng
圆二色性光谱学是研究手性分子结构信息的重要技术。分子固有的弱手性往往要求较长的光程和高浓度的分子。超表面可以产生局部强手性场，增强表面附近的手性光分子相互作用。然而，超表面的损失和结构手性会降低手性分子固有的CD，并诱发干扰分子手性分析的干扰光谱特征。在此，我们实现了非手性二氧化钛的超表面，以增强手性分子的近紫外CD。该装置在波长大于360纳米的情况下是完全无损的，并在近场产生强烈的手性热点。在数值上证明了光学手性增强80倍，CD增强50倍。此外，我们还证明了超表面可以作为保偏镜和增强。
Circular dichroism (CD) spectroscopy is an important technique to investigate the structural information about chiral molecules. The intrinsically weak chirality of molecules often requires long optical paths and high-concentrated molecules. Metasurfaces can generate localized strong chiral fields to enhance chiral light-molecule interactions near the surface. However, losses and structural chirality of metasurfaces can diminish the inherent CD of the chiral molecules and induce interfering spectral features that disturb the chiral analysis of the molecules. Herein, we realize achiral titanium dioxide metasurfaces to enhance the near-ultraviolet CD of chiral molecules. The device is completely lossless for wavelengths greater than 360 nm and produces intense chiral hotspots in the near-field. An 80-fold enhancement of optical chirality is numerically demonstrated, giving rise to a 50-fold enhancement of CD. In addition, we show that the metasurface can function as a polarization-preserving mirror and enha...