▎ 摘　　要

The natural modes (eigenmodes) of graphene-covered circular dielectric micro-cylinders are studied based on the corresponding full-wave electromagnetic eigenvalue problem, in which complex resonance frequencies and corresponding fields are determined numerically. It is shown that the set of complex frequencies splits into two families. The first one corresponds to the modes of the dielectric cylinder perturbed by the graphene cover and the second family represents modes of the graphene cover itself which are plasmon modes. By introducing a transition coefficient, the transformation of the natural modes of the bare dielectric cylinder to the modes of the graphene and the perfectly electric conducting cylinder filled with dielectric are traced. In particular it was shown that the plasmon modes appear not only as a result of the transformation of the inner modes of the perfectly conducting cylinder but also of outer complex modes when the transition coefficient varies from zero to one. In the paper the natural modes are analyzed together with the two-dimensional scattering problem where the cylinder is excited by the H-polarized plane wave. The total and backward scattering cross-sections and the absorption cross-section versus the frequency are presented. It is shown that resonances in the behavior of these cross-sections strongly correlate with the complex frequencies of the natural modes. For a cylinder radius in the micrometer range the principal-mode resonances lay in the THz range. Consequently an important application is sensing at THz frequencies, via measuring the environment-dependent resonance frequencies.