Single nanohole and photoluminescence: nanolocalized and wavelength tunable light source

We are first to demonstrate a broadband, nanometer-scale, and background-free light source that is based on photoluminescence of a single nanohole in an Au film. We show that a nanohole with a diameter of as small as 20 nm in a 200-nm thick Au film can be used for this purpose. Further development of the localized source that involves the use of a photon-crystal microcavity with a Q-factor of 100 makes it possible to create a 30-fold enhanced, narrowband tunable light source and with a narrow directivity of the radiation.