Quasi-effective medium theory for multilayered magneto-dielectric structures (Vol. 45 No.2)

Object-independent cloaking

Maxwell–Garnett theory is the most widely used effective medium theory for the determination of the permittivity/permeability of nano-composite materials. However, it places a serious restriction on the physical dimensions of the constituents, that is, the feature sizes must be smaller than the incident wavelength. Thus, its applicability is limited to the quasi-static regime. An alternative theory has now been proposed by the authors which uses mode-dependent quasi-effective impedances to allow exact calculations of the far field scattering/extinction of complex multi-shell structures regardless of the object physical dimensions.

To demonstrate the physical insights that are to be gained based on this quasi-effective medium theory the authors have studied two practical examples: (i) they consider the problem of surface plasmon hybridization in concentric multi-shell particles, and (ii) they have applied the theory to design an object-independent cloak which consists of an arbitrary shaped object enclosed by a set of concentric shells. The most significant advantages of this new theory are its simplicity, ease of implementation and the important insights the theory provides into the optical properties of complex systems.

D. A. Genov and P. C. Mundru, "Quasi-effective medium theory for multi-layered magneto-dielectric structures", J. Opt. 16, 015101 (2014)
[Abstract]