  We explore the spectral properties of the time-dependent Maxwell's equations
for a plane interface between a metamaterial represented by the Drude model and
the vacuum, which fill respectively complementary half-spaces. We construct
explicitly a generalized Fourier transform which diagonalizes the Hamiltonian
that describes the propagation of transverse electric waves. This transform
appears as an operator of decomposition on a family of generalized
eigenfunctions of the problem. It will be used in a forthcoming paper to prove
both limiting absorption and limiting amplitude principles.
