We study the materials that are composed of metals and insulators. These plasmonic and non-plasmonic materials are ordered in geometric arrangements with dimensions that are fractions of the wavelength of light. A theoretical model is developed to simulate the refractive index of these nano-structured electromagnetic materials which support surface plasmon resonances. Factors contributing to the refractive index sensitivity are explored phenomenologically. Particles with size parameters smaller by much less than 1 have optical properties accurately predicted by the quasi-electrostatic theory while particles with larger size parameters necessitate electrodynamics. We simulate a type of refractive index material composed of metal and insulating dielectric nano-spheres, which are able to sustain the propagation of infrared or visible frequency electromagnetic waves known as surface plasmon polaritons.
