Investigation into Metamaterial Structures Operating at Terahertz Wavelength
Society of Photo-Optical Instrumentation Engineers (SPIE)
Proceedings of SPIE 7592, Reliability, Packaging, Testing, and Characterization of MEMS/MOEMS and Nanodevices IX
Our investigation addresses the modeling, design and fabrication of artificial structures, commonly called metamaterials. Metamaterials enable electromagnetic properties which do not naturally exist from basic structural symmetry. This investigation focuses on the modeling, fabrication and testing of metamaterials at terahertz wavelengths. This research utilizes a foundry fabrication process called PolyMUMPs to construct the metamaterial array. The PolyMUMPS process is commonly used for MEMS devices and consists of three polysilicon and two silicon dioxide layers. An array of split ring resonators consisting of the polysilicon and silicon dioxide layers was constructed. The split ring resonators are an important aspect to the metamaterial because they allow us to take advantage of structural properties such as scaling, resonant frequency response, and magnetic flux. The metamaterial structure obtains its symmetry from the etching process used to isolate the individual patterns. The "as-built" figure of merit (FOM) is defined as the ratio of the real component to the imaginary component of the refractive index. By comparing the analytical and FEM models to identify key limitations of the FOM structures, this investigation will point out manufacturing limitations that can be adjusted to improve the FOM. By gaining a higher ratio to the FOM, this improves the overall performance of the metamaterial structure at the selected wavelength. Through the understanding obtained from the modeling data and actual manufacturing comparison, changes to key parameters which limit the FOM can lead to metamaterial array improvements and ultimately to better components suitable for terahertz applications.