Fig. 8. (a) Schematic illustration of the Cu NW plasmonic-tuned flash welding (PFW) process. (b) Spectral and polarization-dependent simulations of local light absorption for the Cu NW junction from 400 to 800 nm wavelength. The inset shows the field enhancement response under the visible light (wavelength of 600 nm) for light polarized perpendicular/parallel to the first NW. (c) Local heat generation as a function of Cu NW overlap length, which shows the self-limiting nature of the PFW process. The insets show field distribution simulations as a function of Cu NW overlap length. (d) A plane-view SEM image of PFW-treated Cu NWs. (e) A plane-view transmission electron microscope (TEM) image of fused Cu NW junction.¹¹⁵.