A scanning fiber-based microcavity for controlling single molecule emission

The interaction of light and matter in a microcavity depends crucially on the position of the emitter in the spatial field distribution of the resonator mode. In an ideal experiment one would like to place an emitter at will within the mode of the cavity to change the interaction strength in a controllable fashion. Although several efforts have aimed at the realization of such a scheme, its application remains an experimental challenge. Fabry-Perot microresonators constitute a promising route for a controlled coupling of atoms in the gas phase as well as for solid state systems and molecules. Here we present the selective coupling of fluorescent nanoparticles and single molecules to a tunable, fiber-based, scannable microcavity.