Optical nanosensors based on plasmonic nanoparticles have great potential for chemical and biological sensing applications, but their spectral detection resolution is severely constrained by their broad resonance linewidth, and their spatial sensing depth is limited to several tens of nanometres. In a collaboration with Prof. Markus Schmidt (now with IPHT Jena) and co-workers, we demonstrate that coupling a strong dipolar plasmonic resonance of a single metallic nanoparticle to the narrow bandwidth resonances of an optical microcavity may boost the sensing figure-of-merit by up to 36 times. Such a hybrid sensor can be used not only to locally monitor specific dynamic processes in biosensing, but also to remotely detect important film parameters in thin-film nanometrology.

Reference: M. A. Schmidt, D. Y. Lei, L. Wondraczek, V. Nazabal, S. A. Maier: Hybrid nanoparticle?microcavity based plasmonic nanosensors with improved detection resolution and extended remote?sensing ability.Nature Comm. 3, art. no. 1108 (2012). doi: 10.1038/ncomms2109