Investigations On The Propagation And Scattering Properties Of Electromagnetic Wave In Composite Structures With Non-local Response

With the rapid development of nanotechnology, the size of devices reduces to the nanometer level. Nonlocal response is likely to be crucial for propagation and scattering properties of electromagnetic wave. Using the hydrodynamical mode, we derive the wave equation and the frequency dispersion of the longitudinal wave which arises from nonlocal response. Based on the nonlocal response in this paper, we study the two metal multilayer nanostructures, i.e., the air/metal/anisotropic structure and the anisotropic/metal/anisotropic structure. We derive the dispersion relations of surface palsmon polartions in these nanostructures and discuss the dependences of propagation length on the structure and material parameters in anisotropic nanostructure in detail. Numerical results show that there are symmetric and antisymmetric modes when surface palsmon polartions spread in the metal multilayer nanostructures. Comparing with the local mode, we find that the nonlcoal response becomes obvious when the thickness of metal film becomes thinner. At the same time, we find that the propagation length is very sensitive to the anisotropic material.Then, the electromagnetic scattering from a cylinder coated with an anisotropic material is investigated. We discuss the dependences of the extinction cross-section on the structure and material parameters in local and nonlocal model. Numerical results show that the nonlocal response not only causes the shift of main peak in the low frequency, but also produces several subsidiary peaks in high frequency. The thickness of the cover has a tiny influence on main peak, but the subsidiary peaks become greater as the thickness of the cover increases. At the same time, we can control the extinction cross-section by the anisotropic material.