  The near-field spectroscopic information is critically important to determine
the Forster resonant energy transfer(FRET) rate and the distance dependence in
the vicinity of metal surfaces. The high density of evanescent near-field modes
in the vicinity of a metal surface can strongly modulate the FRET in
multichromophoric systems. Based on the previous generalized FRET [A. Poudel,
X. Chen and M. Ratner, J. Phys. Chem. Lett. 7(2016) 955], the theory of FRET is
generalized for the multichromophore aggregates and nonequilibrium situations
in the vicinity of evanescent surface electromagnetic waves of nanophotonic
structures. The classic dyadic green function (DGF) approach to
multichromophoric FRET (MC-FRET) in the existence of evanescent near-field is
established. The classic DGF approach provides a microscopic understanding of
the interaction between the emission and absorption spectral coupling and the
evanescent electromagnetic field. The MC-FRET of the ring structures
demonstrates complicated distance dependence in the vicinity of the silver thin
film. Given the analytic expression of hyperbolic multi-layer thin film, the
generalized coupling due to the metallic thin film is determined by the
scattering DGF above the metal surface. The decomposition of the reduced
scattering DGF by ignoring $S$ wave in the evanescent wave shows how the
interface of the metallic thin films modulates the MC-FRET.

Chemical Physics;Optics