  We apply the Thermal Field Theory methods to study the propagation of photons
in a plasma layer, that is a plasma in which the electrons are confined to a
two-dimensional plane sheet. We calculate the photon self-energy and determine
the appropriate expression for the photon propagator in such a medium, from
which the properties of the propagating modes are obtained. The formulas for
the photon dispersion relations and polarization vectors are derived explicitly
in some detail for some simple cases of the thermal distributions of the
charged particle gas, and appropriate formulas that are applicable in more
general situations are also given.
