Plasmon-Controlled Fluorescence: Beyond the Intensity Enhancement

Control over light absorption and emission using plasmonic nanostructures is an enabling technology, which can dramatically enhance the performances of existing optical and optoelectronic devices, such as solar cells, light-emitting devices, biosensors, and high-resolution fluorescence microscopes. This Perspective takes fluorescence as an example, illustrating how plasmonic nanostructures can control the light absorption and emission of nanoscale optical species. The origins of fluorescence intensity enhancements will be first discussed. Different parameters that can largely affect the interactions between plasmonic nanostructures and fluorophore molecules will be examined, including the distance between the fluorophore molecule and the metal nanostructure and the wavelengths of their respective optical responses. The role of plasmonic nanostructures on fluorescence will then be reconsidered from the perspective of optical nanoantennas. We expect that more functionalities of plasmonic nanostructures as optical nanoantennas will further be discovered in analogy with the radio frequency antenna counterparts.