(a) 3D intensity plot of two particles (1, 2) at time delays: τ = 0, 21.75, and 29.5 fs (left) and comparison of the plasmon signal from the two NPs (right).^[79] (b) Femtosecond FWM nanoimaging of coherent plasmon dynamics in Au film.^[40] (c) Dynamics of photoemission from the gap of a single plasmonic nanoantenna.^[80]