Significant increase of plasmonic surface enhancement has been observed in gold coated micron sized inverse pyramids entrapping a gold nanoparticle. The amplification of both surface enhanced Raman and fluorescence signals was found and it was dependent on the size of the trapped gold nanoparticle. The enhancement was found to be 50 times higher for the 250nm diameter nanosphere, compared to the 50nm one. Finite differential time domain simulations were performed to determine the near-field distribution in the structure and showed that when the nanoparticle protrudes into the hotspot zone of the void, coupling of the electromagnetic field occurs and the plasmon-related near-field enhancement is concentrated into the close vicinity of the nanoparticle, mainly into the gaps around the contact points of the curved sphere and the flat pyramid surfaces.

在包裹金纳米粒子的镀金微米级反金字塔中，观察到等离子体表面增强的显着增加。发现表面增强的拉曼信号和荧光信号的扩增，这取决于被捕获的金纳米颗粒的大小。发现与直径为50nm的纳米球相比，直径为250nm的纳米球的增强作用高50倍。进行了有限差分时域仿真，以确定结构中的近场分布，结果表明，当纳米颗粒伸入空隙的热点区域时，电磁场发生耦合，与等离子体相关的近场增强被集中到纳米粒子的紧密附近，主要是进入弯曲球体和平坦棱锥表面接触点周围的间隙。