  It is known that the near-field spectrum of the local density of states of
the electromagnetic field above a SiC/air interface displays an intense narrow
peak due to the presence of a surface polariton. It has been recently shown
that this surface wave can be strongly coupled with the sheet plasmon of
graphene in graphene-SiC heterosystems. Here, we explore the interplay between
these two phenomena and demonstrate that the spectrum of the electromagnetic
local density of states in these systems presents two peaks whose position
depends dramatically both on the distance to the interface and on the chemical
potential of graphene. This paves the way towards the active control of the
local density of states.
