Fig. 3.

Shaping the phase in hotspot on a plasmonic structure using the resonances of the constituent antennas. (A) Antenna signature measured in a hotpot on a 530-nm single antenna (Left) and the resonance profile retrieved from the fit (Right). (B–D) Corresponding signatures (Left) and resonance profiles (Right) for a 620-nm single antenna and different positions on a coupled 530- to 620-nm asymmetric antenna, demonstrating the engineering of spectral phase in antenna hotspots by mixing resonances with different strengths.