Font Size: a A A

Research On Terahertz Metamaterials

Posted on:2011-04-19Degree:DoctorType:Dissertation
Country:ChinaCandidate:J Q GuFull Text:PDF
GTID:1118330338983213Subject:Photonics technology
Abstract/Summary:PDF Full Text Request
Recently, metamaterials play an more and more important role in the research of the electromagnetic components. Because this kind of artificial material has many novel pr operties a bsent i n nor mal m aterials, it i s w idely used i n t he de sign a nd research o f t erahertz components. In t his t hesis w e s tudied s everal t erahertz metamaterials in detail. The main content is listed below:1, F irst w e r eviewed the co ncept and t he d evelopment o f matematerials. The advantages, challenges and significant of terahertz metamaterial were analyzed, too. We utilized the RLC circuit model and the transmission line model to analyze the SRR array and the Fishnet structure, respectively. Several typical terahertz systems were presented as well as the photolithography process of the sample fabrication.2, The first work is the closed-ring pair metamaterial. The sample was fabricated on the Mylar film by a self-aligned photolithography and measured by t ransmission and reflection THz-TDS. The parameters retrieved from the simulation proved the negative refraction index at 0.69 THz. Transmission model was utilized to analyze the influence of t he r ing's geometry o n t he r esonance, w hich w as a pproved by t he experiments.3, The second work is the YBCO superconducting metamaterial. The SRR based metamaterial was designed by CST and fabricated by photolithography followd by an wet etch in acid. The YBCO metamaterial was investigated experimentally by the cryogenic THz-TDS. Much more pronounced LC and quodrupole resonances were observed w hen t he t emperature was d ecreased b elow t he cr itical t emperature of YBCO. Based on the two-fluid model, the simulation was carried on by changing the conductivity of the YBCO to take account of the change of the temperature, which shows results accordant with the experiments very well.4, The last work is the optical controlled active THz metamterial. In this work a unit cell composed by a rectangular hole and SRRs arrounded was designed. The sample was fabricatied on an SOS wafer by phot olithography and RIE etching. By using optical-pump terahertz-probe system, the optical controlled turn over switch effect of the sample was observed. The simulation is in good accordance with the experminetal results, in which the effect of the optical pump was presented by the conductivity of the silicon film on SOS. The distributions of the electrical filed under various o ptical p ump i ndicated t hat t he switch ef fect ar ises f rom t he ex change between the LC resonance of the SRR and extronamal transmission of the hole array.
Keywords/Search Tags:Terahertz, Metamterial, Negative Refraction Index, SRR
PDF Full Text Request
Related items