Molecular decay rates and emission frequencies in the vicinity of an anisotropic metamaterial

The decay rates and emission frequencies of a fluorescing molecule in the vicinity of an anisotropic metamaterial are studied within a phenomenological model. A special kind of indefinite medium recently shown to have a broadband all-angle negative refraction is studied for its interaction with the emitting dipole in the long wavelength limit at close molecule-substrate distances. In addition, materials of alternating metal-dielectric stratified layers are also studied. For the first kind which consists of a composite of metallic nanowires and a dielectric host, the results show that large molecular decay rates (hence exceedingly short lifetimes) occur when negative refraction takes place within the medium; and large blue-shifts can occur for the emission frequencies of the admolecues. For the stratified layered system, abrupt changes in both the emission lifetimes and frequencies can also take place upon negative refraction, although to a much less extent. These abrupt changes can thus provide signatures for probing the transition to such unusual optical property for the medium via surface-fluorescence experiments. © 2009 Elsevier Ltd. All rights reserved.