Hybrid nanoparticle–microcavity-based plasmonicnanosensors with improved detection resolutionand extended remote-sensing ability

摘要

Optical nanosensors based on plasmonic nanoparticles have great potential for chemical andbiological sensing applications, but their spectral detection resolution is severely constrainedby their broad resonance linewidth, and their spatial sensing depth is limited to several tensof nanometres. Here we demonstrate that coupling a strong dipolar plasmonic resonance ofa single metallic nanoparticle to the narrow bandwidth resonances of an optical microcavitycreates a hybrid mode and discretizes the broad localized resonance, boosting the sensingfigure-of-merit by up to 36 times. This cavity–nanoparticle system effectively combines theadvantages of Fabry–Perot microresonators with those of plasmonic nanoparticles, providinginteresting features such as remote-sensing ability, incident-angle independent resonances,strong polarization dependence, lateral ultra small sensing volume and strongly improveddetection resolution. such a hybrid system can be used not only to locally monitor specificdynamic processes in biosensing, but also to remotely sense important film parameters inthin-film nanometrology.