Active Plasmonic Nanoantennas for Controlling Fluorescence Beams

We propose a tunable plasmonic nanoantenna design that achieves steering fluorescence beams via a voltage signal. The configuration is composed of a nanometallic grating structure coated with a thin luminescent layer and a liquid crystals (LC) cell fixed above as a modulator. The angle-scanned fluorescence spectra show that fluorescence emitted from this metallic grating antenna has a high directivity (divergence angle ≈ 3°) and the beams present a high monochromaticity (full width at half-maximum ≈ 14 nm). More importantly, the fluorescence wavelength can be continuously tuned at a high repetition rate according to the electric signal applied on the LC modulation layer. We further extended the tunable antenna design to a bullseye-shaped nanoantenna to achieve tunable complete-collimated beams. The active control strategy of luminescence based on plasmonic nanoantennas has a great practical significance in developing novel tunable nanoscale light sources.