Study On Surface Plasmon Bandgaps In Sub-wavelength Periodic Metal Microstructures

Since subwavelength metallic materials have great room for development and potential applications, they are investigated widely and intensively on many fields, including condensed matter physics and near fields optics. Surface Plasmons play a vital role in many optical phenomena on the subwavelength dimensions. Surface plasmons(SPs) are light waves that occur at a metal/dielectric interface, where a group of electrons is collectively moving back and forth. Since SPs offer a solution to overcome the difficulties of opto-electronic integrated devices, they have a broad application prospect in plasmonic chips, data storage, metal waveguide, subwavelength imaging, photolithography, microscopy and bio-photonics, et al. Recently, with the rapid development of micro-fabrication technology and theoretical study, plasmonics has become one of the frontier of physics. In the following, we present our results on how to manipulate the band structure of surface plasmons.Firstly, based on the formulation of binary periodic gratings, we do research on the characteristics of surface plasmons band structure by dint of rigorous coupled-wave analysis(RCWA). The effects of certain geometric parameters on the surface plasmons band-gap are calculated and discussed. Such analysis is also been done in the case of dual-periodical gratings.Secondly, we manipulate the enhanced transmission of light through sub-wavelength hole arrays by means of the band structure of surface plasmons. According to the numerical simulations based on finite difference time domain method(FDTD), it was found that with the combination of sub-wavelength hole arrays and grooves, the surface plasmons band-gap would be manipulated, resulting to the inhibition of particular peaks in transmission spectrum. These numerical calculations have been verified partly by experiments, and further experimental work is continuing.In conclusion, our work provides further studies of surface plasmons on sub-wavelength periodic metallic microstructures with theoretical basis and technological support. These studies provide new knowledge about the interactions between light and compound periodic metallic nanostructures,which could provide reference for the design of subwavelength photonic devices, as well as opening new perspective in manipulating the electromagnetic waves.