CdSe-single-nanoparticle based active tips for near-field optical   microscopy
  We present a method to realize active optical tips for use in near-field optics that can operate at room temperature. A metal-coated optical tip is covered with a thin polymer layer stained with CdSe nanocrystals or nanorods at low density. The time analysis of the emission rate and emission spectra of the active tips reveal that a very small number of particles - possibly down to only one - can be made active at the tip apex. This opens the way to near-field optics with a single inorganic nanoparticle as a light source. 
N. Chevalier, M. J. Nasse, J .C. Woehl, P. Reiss, J. Bleuse, F.   Chandezon and S. Huant