  The problem of enhanced molecular emission in close proximity to dielectric
and metallic interfaces is of great importance for many physical and biological
applications. Here we present an exact treatment of the problem from the view
point of classical electromagnetism. Self-consistent analytical theory of the
surface fluorescence enhancement is developed for configurations consisting of
an emitter in proximity to core-shell metal-dielectric nanoparticles. The
dependence of the fluorescence enhancement on the excitation laser and
fluorescence frequencies and distance of the emitter to the nanoparticle
interface are studied. The developed theory predicts enhanced fluorescence at
intermediate distances as well as emission quenching into non-radiative surface
plasmon (SP) modes dominating the response for short distances. The conditions
for optimal emission enhancement for two core-shell configurations are
determined. The theory can be applied toward analyzes and optimization of
various applications related to SP enhance fluorescence spectroscopy.
