Correlated nano-spectroscopy of coherent and incoherent electron dynamics in plasmonic nano-tips

Combined four wave mixing and hot electron photoluminescence from plasmonic nanotips are observed in adiabatic nanofocusing of ultrafast pulses. Based on the electronic decoherence and hot electron evolution, we infer different relaxation and dissipation pathways from few-fs to ns timescales. The results allow for expanding upon current models of carrier dynamics in metals, applicable for isolated plasmonic nanostructures, as well as thermal transport with hot electrons between tip and sample. The approach has implications on near-field localization and dissipation in different modalities of optical nano-imaging with ultrafast laser pulses.