Holst Centre/imec-nl, High Tech Campus 31, 5656 AE Eindhoven, The Netherlands.
ACS Nano. 2011 Jun 28;5(6):5151-7. doi: 10.1021/nn201227b. Epub 2011 May 20.
We demonstrate an improvement by more than 1 order of magnitude of the figure of merit (FoM) of plasmonic nanoparticle sensors by means of the diffractive coupling of localized surface plasmon resonances. The coupling in arrays of nanoparticles leads to Fano resonances with narrow line widths known as surface lattice resonances, which are very suitable for the sensitive detection of small changes in the refractive index of the surroundings. We focus on the sensitivity to the bulk refractive index and find that the sensor FoM scales solely with the frequency difference between the surface lattice resonance and the diffracted order grazing to the surface of the array. This result, which can be extended to other systems with coupled resonances, enables the design of plasmonic sensors with a high FoM over broad spectral ranges with unprecedented accuracy.
我们通过局域表面等离激元共振的衍射耦合，将等离子体纳米粒子传感器的优值（FoM）提高了一个数量级以上。纳米粒子阵列中的耦合导致了具有窄线宽的 Fano 共振，即表面晶格共振，非常适合于周围折射率微小变化的灵敏检测。我们关注于对体折射率的灵敏度，并发现传感器的 FoM 仅与表面晶格共振和衍射阶之间的频率差有关，该衍射阶掠过阵列表面。这个结果可以扩展到具有耦合共振的其他系统，从而能够设计出具有高 FoM 的等离子体传感器，其在前所未有的精度下具有宽光谱范围。
