Surface-Enhanced Raman Scattering (SERS) and Surface-Enhanced   Fluorescence (SEF) in the context of modified spontaneous emission
  Surface Enhanced Raman Scattering (SERS) and Surface-Enhanced Fluorescence (SEF) are studied within the framework of modified Spontaneous Emission (SE), and similarities and differences are highlighted. This description sheds new light into several aspects of the SERS electromagnetic enhancement. In addition, combined with the optical reciprocity theorem it also provides a rigorous justification of a generalized version of the widely used SERS enhancement factor proportional to the fourth power of the field ($|E|^4$). We show, in addition, that this approach also applies to the calculation of Surface-Enhanced Fluorescence cross-sections thus presenting both phenomena SERS and SEF within a unified framework. 
E. C. Le Ru and P. G. Etchegoin