Gap-type metallic nanostructures are widely used in catalytic reactions, sensors, and photonics because the hotspot effect on these nanostructures supports giant local electromagnetic field enhancement. To achieve hotspots, researchers devote themselves to reducing gap distances, even to 1 nm. However, current techniques to fabricate such narrow gaps in large areas are still challenging. Herein, a new coupling way to boost the sub-10 nm plasmonic nanogap array is developed, based on the plasmon-triggered optical waveguide resonance via near-field coupling. This effect leads to an amplified local electromagnetic field within the gap regions equivalent to narrower gaps, which is evidenced experimentally by the surface-enhanced Raman scattering intensity of probed molecules located in the gap and the finite-difference time-domain numerical simulation results. This study provides a universal strategy to promote the performance of the existing hotspot configurations without changing their geometries.

中文翻译：

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通过等离子触发波导共振增强亚 10 nm 纳米间隙阵列

间隙型金属纳米结构广泛用于催化反应、传感器和光子学，因为这些纳米结构上的热点效应支持巨大的局部电磁场增强。为了实现热点，研究人员致力于将间隙距离减小到 1 nm。然而，目前在大面积制造这种窄间隙的技术仍然具有挑战性。在此，基于等离子体触发的光波导共振通过近场耦合，开发了一种新的耦合方式来增强亚 10 nm 等离子体纳米间隙阵列。这种效应导致间隙区域内放大的局部电磁场相当于更窄的间隙，位于间隙中的探测分子的表面增强拉曼散射强度和有限差分时域数值模拟结果通过实验证明了这一点。这项研究提供了一种通用策略，可以在不改变其几何形状的情况下提升现有热点配置的性能。