High quality electromagnetic oscillations in inhomogeneous coated microsphere

We study transmission of the electromagnetic waves of the near infrared spectral range through the metal-semiconductor spherical stack with a radial dependence of the effective dielectric permittivity of semiconductor layers. Such an inhomogeneity is formed by a high concentration of carriers at the interfaces of thin semiconductor-metal structures and its spatial scale can be of order of a width of narrow metallic layers. Because of complexity of analytical solution, we develop numerical approaches, which allow us to study the features of the electromagnetic wave propagation through such a nonuniform structure. The eigenfrequencies and radial distributions of fields are also discussed.