Terahertz Wave Metametarial Filters Based on Superconducting Bi2212 Thin Films

2015-08-28
Demirhan, Yasemin
Alaboz, Hakan
Semerci, Tuğçe
Özyüzer, Lütfi
Nebioğlu, Mehmet Ali
Takan, Taylan
Altan, Hakan
Sabah, Cumali
Terahertz (THz) frequency range lying between 0.1 to 10 THz, and its technology has attracted vast interests due to its wide application areas [1]. The importance of developing passive and active devices which work in terahertz wave frequencies is ever more increasing in this popular field [1-2]. Superconducting devices are excellent candidates due to their distinctive advantages of extremely low noise, low power consumption and high frequency operation [3-4]. In addition to these, although high-Tc superconducting low-loss metamaterial devices have been designed, thin films based on (Bi2212) Bi2Sr2CaCu2O8+x have not been utilized. In this study, we present two types of filters for the terahertz (THz) frequency range. Our goal is to develop narrow band THz band-pass filters based on superconducting metamaterials. In contrast to metals, the complex conductivity of superconductors intrinsically depends on the magnetic field, temperature, and applied optical fields. Active metamaterial structures can therefore be realized by directly controlling the conductivity of the superconducting elements without introducing additional elements. ITO, Ti and Cu were chosen as the metallic layer due to their good attachment to the substrate. These films were grown in high vacuum magnetron sputtering system. Terahertz resonant filters were lithographically fabricated from 90-300 nm metal films grown on a 1 mm thick quartz substrate. After fabrication, the samples were measured using a Bruker Vertex V80 FTIR spectrometer. Transmission measurements have shown center frequencies and bandwidths close to the design predictions. The measured results of metal mesh filters showed an insertion loss, which is due to the finite conductivity of the metal films and some loss in the substrate. Finally the created structures were also characterized using time-domain THz spectroscopy (THzTDS) and CW-THz measurement systems. CST microwave program is used for simulation studies of transmittance properties of filter structures and compared with experimental results. Furthermore, superconducting Bi2212 thin films will be used for fabrication of filter structures.
Citation Formats
Y. Demirhan et al., “Terahertz Wave Metametarial Filters Based on Superconducting Bi2212 Thin Films,” presented at the PHOTONICA 2015 the Fifth international school and conference on photonics, (24 - 28 Augus 2015), Belgrade, Serbia, 2015, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/75513.