Subwavelength imaging from a multilayered structure containing interleaved nonspherical metal-dielectric composites

A thin multilayered structure with interleaved nonspherical metal-dielectric composites slices and dielectric slices may be modeled as the metamaterial with anisotropic permittivity. The signs of diagonal elements of the permittivity tensor can be controlled by the particles' shape, the volume fraction of metal particles, and the incidental wavelengths. To one's interest, when the spheroidal nanoparticles are oblate in shape, the wavelength range in which components of the permittivity have different signs is widened, and the magnitude of optical absorption band becomes weak. Since both physical anisotropy and low absorption are helpful for improving the subwavelength image resolution, the multilayered structure containing metal-dielectric composite layer of nonspherical particles may be designed as a superlens device. In addition, the incident wavelength and the number of nanolayers are found to play crucial roles in enhancing the evanescent field performance too.