Metal Subwavelength Hole Arrays Of Terahertz Transmission Characteristics

In this thesis, selecting transmission property of sub-wavelength metallic holes array are investigated using THz time-domain spectroscopy (THz-TDS). We study the factors that affect this property.When terahertz radiation irradiate the surface of metal sub-wavelength holes array, there will be transmission peak at some frequency because of the surface plasmon resonant. This is the selecting transmission property of metal sub-wavelength holes array. Many factors affect this property, such as the lattice constant of the array, dielectric of the metal and the medium, the thickness of the medium and so on. We mainly discuss the influence of the frequency and intensity of the transmission peak by the thickness of the medium and the foil. Our work is mainly about:(1) Attaching the medium film to one side of the array. We found the changing of the thickness affect the frequency and intensity of the transmission peak. When the thickness is increasing, the frequency becoming lower and the intensity decreasing.(2) Attaching the medium film to both sides of the array. The phenomenon is the similar to that to one side. But in our experiment, we found when the film is thin (54μm), the intensity of the transmission peak is greater than that of no film. This phenomenon explains that attaching thin film to both sides of the holes array will enhance the selecting transmission property.(3) When the same film is attached to one side of the holes array and both sides of the array, the result is different. The frequency of the peak in the first situation is a little higher than that in the second situation, and the intensity of the peak is more greater.(4) When other factors are the same, the holes array carved in the thinner foil has a transmission peak of lower frequency and greater intensity than that carved in the thicker one.What we discussed above will give some information for making terahertz parts.