Diffraction‐grating‐enhanced light emission from tunnel junctions

We report the observation of highly polarized, angle‐tunable visible light emission from Al‐AlO_x‐Ag tunnel junctions fabricated on holographic gratings. From the angular dependence of the emission frequency we identify the electromagnetic mode responsible for the emission. The mode is surface plasmonlike with a dispersion that closely follows the light line. This is in contrast to the much lower phase velocity ’’junction’’ mode believed responsible for the light emission on surface‐roughened tunnel junctions. We argue that both modes should be considered in describing the emission from these devices.