  Directing and polarizing the emission of a fluorophore is of fundamental
importance in the perspective of novel photonic sources based on emerging
nano-emitter technologies. These two tasks are usually accomplished by a
sophisticated and demanding structuring of the optical environment in which the
emitter is immersed, or by non-trivial chemical engineering of its geometry
and/or band structure. In this paper, the wavelength and polarization selective
spontaneous emission from a dye-embedded in a Metal/Insulator/Metal (d-MIM)
nanocavity is demonstrated. A push-pull chromophore with large Stokes shift is
embedded in a MIM cavity whose resonances are tuned with the spectral emission
band of the chromophore. Angular and polarization resolved spectroscopy
experiments reveal that the radiated field is reshaped according to the angular
dispersion of the nanocavity, and that its spectrum manifests two bands with
different polarization corresponding to the p- and s-polarized resonances of
the cavity. The d-MIM cavities are a highly versatile system for polarization
and wavelength division multiplexing applications at the nanoscale, as well as
for near-field focused emission and nanolenses.
