Surface magnon-polaritons (SMPs) are a type of quasiparticle in condensed matter physics. They arise from the coupling of incident electromagnetic (EM) radiations to the magnetic dipole polarization in the surface layers of a solid. Magnons are analogous to other forms of polaritons, such as plasmons and phonons, but represent an oscillation of the magnetic component of the solid's EM field rather than its electric component or a mechanical oscillation in the solid's atomic structure.