Preparation And Exotic Optical Properties Of Micro- And Nanostructures Of Metal Films

Metal/dielectric periodically structured films exhibit unique optical properties such as extraordinary optical transmission and negative refraction. They have become one of the most active research topics because of their potential applications in sub-wavelength optics and optoelectronic devices.We experimentally fabricated metal/dielectric films with periodically structured surfaces in this thesis. Three main steps, self-assembly of colloidal crystal, PDMS soft lithography, and multilayer deposition, were used to fabricate large-scale periodically structured metal/dielectric films. This method can fabricate large-scale high-quality metal/dielectric films with submicrometer periodicity at low cost.The main contents of the thesis are described as follows:1. Large-scale two-dimensional concavity metal/dielectric multilayer structure with submicrometer periodicity was fabricated by self-assembly of colloidal crystal, PDMS soft lithography, and multilayer deposition into the PDMS cavity array, and its transmission properties were experimentally measured as the number of metal layer. For the samples with one metal layer, two transmission pass bands have been observed in the sample due to the excitation of surface plasmon polaritons (SPPs). The peak positions of the pass bands depend on the periodicity of the colloidal crystal. The transmission spectra highly depend on the incident angle for both s-and p-polarized light. For the samples with two or more metal layers, a new pass band due to interference appears. This band is not as sensitive to the incident angle for s-or p-polarized light as the SPP induced band is, and its position depends on the thickness of the metal and dielectric layer. As the number of metal layer increases, the intensity of the SPPs induced band decreases faster than that of the interference related band. For the samples with four metal layers, only the interference related band is clearly observed.2. Metal film perforated with holes and concavity metal film without holes were fabricated by deposition metal onto the colloidal crystal and PDMS cavity array, respectively. Their transmission properties were experimentally measured. The position of the transmission pass bands of the concavity metal film without hole matches with dispersion relation of SPP at the infinite ideal metal/dielectric interface, while that of the metal film with hole does not. By simulating the samples’ electric-field distribution at transmission pass band, we explain the physical mechanisms behind the experimental results.3.By simulating and parameters retrieval,we study the Negative Refractive Index of the metal-dielectric-metal (MDM) metamaterials.