INPAC-Institute for Nanoscale Physics and Chemistry, K U Leuven, Leuven, Belgium.
Nano Lett. 2011 Feb 9;11(2):391-7. doi: 10.1021/nl102991v. Epub 2011 Jan 25.
The detection of small changes in the wavelength position of localized surface plasmon resonances in metal nanostructures has been used successfully in applications such as label-free detection of biomarkers. Practical implementations, however, often suffer from the large spectral width of the plasmon resonances induced by large radiative damping in the metal nanocavities. By means of a tailored design and using a reproducible nanofabrication process, high quality planar gold plasmonic nanocavities are fabricated with strongly reduced radiative damping. Moreover, additional substrate etching results in a large enhancement of the sensing volume and a subsequent increase of the sensitivity. Coherent coupling of bright and dark plasmon modes in a nanocross and nanobar is used to generate high quality factor subradiant Fano resonances. Experimental sensitivities for these modes exceeding 1000 nm/RIU with a Figure of Merit reaching 5 are demonstrated in microfluidic ensemble spectroscopy.
金属纳米结构中局域表面等离激元共振波长位置的微小变化的检测已成功应用于生物标志物的无标记检测等领域。然而，实际应用通常受到金属纳米腔中大辐射阻尼引起的等离子体共振大光谱宽度的影响。通过精心设计和使用可重复的纳米制造工艺，制造出具有大大降低辐射阻尼的高质量平面金等离子体纳米腔。此外，通过进一步的基底刻蚀，实现了传感体积的大幅增强和灵敏度的相应提高。纳米十字和纳米棒中的亮暗等离子体模式的相干耦合用于产生高品质因子亚辐射范德瓦尔斯共振。在微流控整体光谱学中，这些模式的实验灵敏度超过 1000nm/RIU，品质因数达到 5。
