Spontaneous emission enhancement of a single molecule by a double-sphere   nanoantenna across an interface
  We report on two orders of magnitude reduction in the fluorescence lifetime when a single molecule placed in a thin film is surrounded by two gold nanospheres across the film interface. By attaching one of the gold particles to the end of a glass fiber tip, we could control the modification of the molecular fluorescence at will. We find a good agreement between our experimental data and the outcome of numerical calculations. 
K.-G. Lee, H. Eghlidi, X-W. Chen, A. Renn, S. G\"otzinger, V.   Sandoghdar
physics.optics quant-ph