Fig. 1
From: Antenna surface plasmon emission by inelastic tunneling
Principle of antenna surface plasmon emission by inelastic tunneling (ASPEIT). a Schematic of the device consisting of a gold patch antenna (thickness 50 nm and width D) on an aluminum film (thickness 25 nm) with a 3-nm-thick tunnel barrier of AlOx in between. Gap plasmons propagating along the x-axis under the gold patch are reflected at the edges forming a Fabry–Perot cavity. The surface plasmons transmitted at the edges propagate along the Al/air interface. They are observed by leakage radiation microscopy through a finite thickness of Al. When applying a voltage bias V, SPPs can be excited by inelastic tunneling. b Energy level diagram for the metal–insulator–metal (MIM) tunnel junction with a voltage bias V. The black arrow shows the maximum electron energy loss, which is the maximum plasmon energy. c Optical microscope image showing the periodical antenna junction (inside the white square). A SEM image shows a zoom of the array of linear antennas (width D = 128 nm, period 400 nm)
