Angle and Polarization Selective Spontaneous Emission in Dye-doped Metal/Insulator/Metal Nanocavities

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.