Study On PhotoConductive Terahertz Source And Terahertz Wire-grid Polarizers

Because of the special situation of the THz radiation in electromagnetic wave spectrum and its outstanding performances, the relative research on the THz radiation generation and application has become a hot spot. But have great difficulties in generation and detection of electromagnetic fields at these wavelengths. Thus, the research has been done in this field is pretty limited now. In practical application terahertz radiation wave should have wide bandwidth and greater radiation power. Photoconductive antenna can meet these requirements and has larger optical conversion efficiency. The use of antenna arrays can emit even high power terahertz radiation. Therefore, using photoconductive antenna to generate terahertz radiation has become one of the most applied practical technologies.In this mention, the theoretical and experimental investigation of THz pulse generation and detection techniques. Based on the numerical analysis of various processes and parameters using photoconductive antenna to generate terahertz radiation. In addition, we produced wire-grid polarizers, this work could be useful for the future research. The main research work summarized as follows:First, we summarized the mechanism of terahertz radiation, terahertz radiation and detection methods based on photonics and electronics.Secondly, we summed up the impact of photoconductive antenna to generate a terahertz wave power factor.according to Maxwell’s electromagnetic theory in detail derived THz near-field and far field expressions.Thirdly, on the basis of studying theoretical models using photoconductive antenna to generate THz radiation, we design experiment of a photoconductive antenna for generating terahertz wave, studied the laser pumping power and the applied bias voltage on the photoconductive antenna to generate THz wave power influence. And we analyzed the saturation phenomena of the THz radiation generated by large aperture We found that THz radiation characteristics are closely related to the above-mentioned factors. So they should be considered entirely when a terahertz radiation system is designed and optimized.Finally, theoretical and experimental researches on A have been taken out. Polarization characteristics of the extinction ration is investigated in our experiment, Our work has reference value to the further research about more complex sub-wavelength metallic structures.