Integrating lattice and gap plasmonic modes to construct dual-mode metasurfaces for enhancing light–matter interaction

基于等离激元晶格和间隙模式构建双共振超构表面及其光与物质相互作用增强研究

Photonic structures with optical resonances beyond a single controllable mode are strongly desired for enhancing light±matter interactions and bringing about advanced photonic devices. However, the realization of effective multimodal photonic structures has been restricted by the limited tunable range of mode manipulation, the spatial dispersions of electric fields or the polarization-dependent excitations. To overcome these limitations, we create a dualmode metasurface by integrating the plasmonic surface lattice resonance and the gap plasmonic modes;this metasurface offers a widely tunable spectral range, good overlap in the spatial distribution of electric fields, and polarization independence of excitation light. To show that such dual-mode metasurfaces are versatile platforms for enhancing light±matter interactions, we experimentally demonstrate a significant enhancement of second-harmonic generation using our design, with a conversion efficiency of 1±3 orders of magnitude larger than those previously obtained in plasmonic systems. These results may inspire new designs for functional multimodal photonic structures.

克服光子结构中只有单个可控共振模式的问题对于增强光-物相互作用和实现先进光子器件具有重要意义.然而,由于模式调控的可调范围有限、电场增强的空间分布差异或模式激发具有偏振依赖等因素的限制,构建可调的多共振的光子结构一直受到限制.为了克服这些局限,本文将等离激元表面晶格共振模式和间隙等离激元模式相结合,构建了一种双共振超表面体系,该体系具有覆盖可见光到近红外波段的光谱可调范围以及良好的电场增强空间重叠性的特点.为了证明该双共振超构表面的优势,我们研究了该体系的二次谐波效应,发现该双共振超构表面的二次谐波转化效率比以往等离激元体系效率高1–3个数量级.以上结果显示,我们的发现为制备基于多模式共振光子结构的功能化器件提供了一个有效方案.