Terahertz Resonance And Scattering Experiment Of Subwavelength Structure At Dielelectric-metal Surface

By making some subwavelength particles at the perfect electric conductor(PEC), onecan get a subwavelength structure. When electromagnetic wave penetrates through thesubwavelength structure, there are peaks in the transmission spectrum, that’s theenhancement of transmission. It can allow people to get over the limit of diffraction. Theelectromagnetic wave is very sensitive to the geometry of the subwavelength structure, soelectromagnetic wave controlled in subwavelength scale can come true through changing thegeometric parameters of the structure. The applications are very promising. But it is not clearthat the relationship between resonant frequency and the geometric parameters.In this thesis the mature method Printed circuit board(PCB) technology is creativelyintroduced to manufacture the subwavelength structure. The resonant experiments interahertz through Terahertz Time Domain Spectroscopy(THz TDS) are researched. Somerelationships between resonant frequency and the geometric parameters are found byanalyzing the transmission and reflection spectrum. This work can make some foundation tomanufacturing terahertz devices.In this thesis, we did some work as follows:(1) By using the miniature terahertz Time Domain Spectroscopy system, the so calledMini z, we analysed the transmission and reflection spectrum of some subwavelengthstructures through the newly developed terahertz time domain spectroscopy. We found thatthe resonant frequency move monotonously as the increasing of filling fraction of thestructure. When giving a cell gap D minus A, the resonant frequency moves monotonouslyto lower frequency as the increasing of filling fraction. These results may find applications incontrolling terahertz and microwave in spatial and frequency domain.(2) We introduced the subwavelength structures into terahertz imaging. We set theterahertz imaging of the graph as reference, and then got its terahertz imaging by combine itand the subwavelength structure together. As a result, we got clearer pictures than thereference at some lower frequency through Terahertz Time Domain Spectroscopytechnology. It is proved by the experiment that the subwavelength structure can improvespace resolution of terahertz imaging.