Metamaterials Preparation And Optical Properties Studies

On the process of prospecting for manipulating light, artificially engineered materials, metamaterials, draw a good deal of attention. The dielectric photonic crystal (PC) and metal/dielectric photonic crystal (surface plasmonic crystal, SPC) with subwavelength feature become increasingly important research directions for the exciting new physical and optical properties.The purpose of this thesis is to fabricate colloidal photonic crystal (CPC) and surface plasmonic crystal, of which the parameters can be manipulated with the approaches of self-assembly and thermal evaporation. Furthermore, we have done cyber-simulations of the several models through Ansoft HFSS software. It is accessible for the minor diameter polystyrene spheres to get the large-area and high-quality PC with self-assembly. It needs a bunch of experiments and fining tune the technological parameters to improve the surface morphology and decrease the defects. The thesis is composed of three parts as follows:1. Use various ways of self-assembly, such as Drop coat% Spinning and vertical self-assembly, to find out an optimal method which can get large-area and high-quality CPC and fine tune the technological parameters of the method. Use the samples we made as substrates to deposit an Ag layer with 50nm to get the SPC. We find that the surface morphology of the CPC is much better which if the diameter matches with the evaporation temperature and turbid liquid volume fraction. All the samples of SPC we got have performed the enhanced transmission phenomenon at the optical wavelength scale and the major transmission peaks dependent on the diameter. As the diameter getting larger, the transmission wavelength red shifts.2. We take advantages of HFSS software to obtain the simulated details and parameters that approximate to the measurements. On the process of simulations we have found that the analogue results and laboratorial measurements have the same trend in enhanced transmission. As the diameter getting larger, the transmission bottom of PCs red shifts. As the period size getting larger, the enhanced transmission peak red shifts. The intensity of the peak decreases with the thicker Ag layer, but the peak not move.3. We have tried to fabricate the SPC with two beam of light of interference lithography (IL) and thermal evaporator. The sample has smaller period with lager angle between two beams. The sharpness has something to do with the intensity of the light.