Terahertz Filter Basded On Subwavelength Metallic Structure Arrays

Sub-wavelength metallic structure arrays (SMSA) are of particular interest in Terahertz (THz) regime owing to their customizable electromagnetic properties. It has been demonstrated that SMSA are promising candidates for overcoming the many limitations of the terahertz technology. In this dissertation we studied several terahertz SMSA in detail. The main research works and conclusions are as following:1. SMSA with different shape, lattice constant, material was investigated by using THz time domain spectroscopic system. Experiments and simulations discovered the contribution of the factors of array in transmission characteristics.2. The transmission characters of metal strip arrays at terahertz range were investigated. The experiments and simulations verified that the resonance frequency and bandwidth of metal strip dependent on the length of the rectangular. We proposed a composed single-layer SMSA assembled by two metal strips with different length. The transmission spectra exhibited multiple band or a broaden band characters. This single-layer SMSA has a potential application in THz filter, polarizer, reflector fabricated and provides a new method for the THz devise designing.3. A hybrid SMSA assembled by a metal mesh and an split ring resonators (SRRs) within a unit cell was proposed. We experimentally demonstrated the transmission characteristics of this structure by changing the relative position of SRRs and metal mesh. The simulated electric field redistribution supported the dependence between the position of the two components and the transmission response. The unique resonance characteristics of the composite structure made it an excellent candidate for developing tunable terahertz components via integration with the MEMS technology.4. A new data process by considering multi-reflection within the meta-film was applied to retrieve the complex permittivity of ultrathin metamaterial film at THz frequency. We experimentally investigated the transmission of an "L" shape metamaterial under two different illumination polarizations. The retrieve process was very convenient because it need only transmission efficient. This method was proved to be a convenient and reliable tool for characterizing optical properties of the ultra thin metamaterial and other dielectric thin films which cannot be done by traditional THz time-domain spectroscopy.