The light emitted by small-particle tunnel junctions is partially polarized. The excess light polarized perpendicular to the junctions is possibly due to the radiative decay of localized surface plasmons that are excited by tunneling electrons. Both the angular distribution and the intensity versus photon energy of this light are in agreement with recent theoretical calculations based on the excitation and radiative decay of surface plasmons in a small metal particle located above a metal film.

• Received 16 January 1979

DOI:https://doi.org/10.1103/PhysRevLett.42.912