Excitation conditions for surface plasmons at a planar metal-dielectric interface
Surface Plasmons : Physical Principles and Applications

The electromagnetic field in a vacuum is represented in terms of two vectors, the electric field E and the magnetic field B. The presence of matter in the space occupied by these vectors requires the introduction of three other vectors, D, H and J, respectively called electric displacement, magnetic field in matter and electric current density. These vectors, whose components are expressed in an orthonormal Cartesian reference frame (x, y, z ), are linked by the following equations (two scalar equations and two vector equations):