(color online) (a) Upper part: SEM image of 725nmlong Au nanowire on Si substrate (scale bar is 250 nm). Lower part: CL images measured at wavelengths of 592, 640, and 730 nm from the nanowire (from Ref. [90], Fig. 1). (b) Left: schematic of experiment. Angular distribution of emission occurs when the tip is moved to a different position on the gold nanoparticle. Right: Energy transfer schematic of Ref. [96]. (c) Electron microscope image of lateral tunnel structure: electrically connected single crystalline gold nanoantenna loaded with coated gold nanoparticles on glass substrate (V + : applied voltage; e⁻: electron flow; hν: light emission). Second: tunnel gap with applied voltage (EF, Fermi energy, and electrochemical potential of Ref. [99], Fig. 1).