Efficient suppression of radiation damping in individual plasmonic resonators: towards high-Q nano-volume sensing

Recent results on radiation damping suppression in individual plasmonic resonators using conformal bending of the structure, which suppresses the electric-dipole response in favor of magnetic dipole one, are overviewed. It is demonstrated that bending of linear plasmonic nano-antennas increases significantly their Q factors above the electrostatic limit while preserving the nature of resonance along with its exceptional features, such as linear size-dependent tunability and robust field enhancement. The approach, which makes use of strong lateral confinement exhibited by the slow plasmonic modes (slow-SPPs) bound to ultra-narrow metallic structures, turned out to be quite general, and its experimental demonstration has been attained with circularly curved nano-rod antennas. Furthermore, this approach suggested novel configurations of plasmonic single particle nanosensing with enhanced features, allowing record-high figures of merit along with unprecedented spatial resolution in nanofiber-based split-cylinder structures.