  Leakage-radiation microscopy of a thin gold film demonstrates the ability of
an ensemble of fluorescent diamond nanoparticles attached onto the apex of an
optical tip to serve as an efficient near-field surface-plasmon polariton
launcher. The implementation of the nanodiamond-based tip in a near-field
scanning optical microscope will allow for an accurate control on the launching
position, thereby opening the way to scanning plasmonics.
