Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Publisher: search.filters.publisher.IOP Publishing Ltd.Subject: search.filters.subject.Terahertz (THz) waves

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Now showing 1 - 3 of 3
  • Article
    Citation - WoS: 13
    Citation - Scopus: 13
    Fourcross Shaped Metamaterial Filters Fabricated From High Temperature Superconducting Ybco and Au Thin Films for Terahertz Waves
    (IOP Publishing Ltd., 2017) Demirhan, Yasemin; Özyüzer, Lütfi; Nebioğlu, Mehmet Ali; Mulla, B.; Demirhan, Yasemin; Altan, Hakan; Sabah, Cumali; Özyüzer, Lütfi; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of Technology
    In this study, we present a new, unique fourcross shaped metamaterial terahertz (THz) filter fabricated from both gold thin films and YBa2Cu3O7-δ high Tc superconducting thin films. A commercial electromagnetic simulation software, CST Microwave Studio, is used to design and optimize the metamaterial filter structures. The proposed fourcross shaped rectangular filter structure consists of periodic metallic rings where strip lines are located at the sides of the ring. Fourcross metamaterial filters are fabricated by using e-beam lithography and ion beam exhing techniques. Terahertz time-domain spectroscopy measurements validated the design predictions for both the center frequencies and bandwidths of the resonances due to the fourcross structures. The resonance switching of the transmission spectra was investigated by lowering the temperature below the critical transition temperature. This resonance switching effect is not observed in filters made up of metals. This novel fourcross rectangular resonator with a temperature-dependent resonance behavior holds great potential for active, tunable and low loss THz devices for imaging, sensing, and detection applications.
  • Article
    Citation - WoS: 39
    Citation - Scopus: 40
    Interferometer Measurements of Terahertz Waves From Bi 2sr 2cacu 2o 8+d Mesas
    (IOP Publishing Ltd., 2012) Türkoğlu, Fulya; Köseoğlu, Hasan; Demirhan, Yasemin; Özyüzer, Lütfi; Preu, Sascha; Özyüzer, Lütfi; Şimşek, Yusuf; Müller, P.; Yamamoto, T.; Kadowaki, K.; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of Technology
    We fabricated rectangular mesa structures of superconducting Bi 2Sr 2CaCu 2O 8+d (Bi2212) using e-beam lithography and Ar ion beam etching techniques for terahertz (THz) emission. c-axis resistance versus temperature (R-T), current-voltage (I-V) characteristics and bolometric THz power measurements were performed to characterize Bi2212 mesas. The emission frequency of mesas was determined using a Michelson interferometer setup which also demonstrates polarized emission. Interference patterns of THz radiation from Bi2212 mesas were detected by various detectors such as a liquid helium cooled silicon composite bolometer, a Golay cell and a pyroelectric detector. An emitted power as high as 0.06mW was detected from Bi2212 mesas. For the first time, most of the pumped power was extracted as THz emission from a Bi2212 mesa. The radiation at 0.54THz was detected using the Michelson interferometric setup.
  • Article
    Citation - WoS: 40
    Citation - Scopus: 45
    Terahertz Wave Emission From Intrinsic Josephson Junctions in High- Tc Superconductors
    (IOP Publishing Ltd., 2009) Özyüzer, Lütfi; Şimşek, Yılmaz; Özyüzer, Lütfi; Türkoğlu, Fulya; Kurter, Cihan; Welp, U.; Koshelev, A. E.; Gray, Kenneth E.; Kwok, W. K.; Yamamoto, T.; Kadowaki, K.; Koval, Yu I.; Wang, Huabing; Müller, Paul H.; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of Technology
    Recently, we experimentally demonstrated that rectangular mesa structures of intrinsic Josephson junctions (IJJ) in Bi2Sr2CaCu 2O8+d (Bi2212) can be used as a compact solid-state generator of continuous, coherent and polarized terahertz (THz) radiation. In the present work, we will exhibit tall mesas (over 600 junctions) which were fabricated using UV lithography, e-beam lithography with photoresist and e-beam lithography with a Ti selective etching technique. We will present measurements of the c-axis resistance as a function of temperature and of current-voltage characteristics of THz emitting mesas with lateral sizes ranging from 30 × 300 to 100 × 300νm2. Furthermore, we will discuss the dependence of the characteristics of the mesa structures on the oxygen doping level of the Bi2212 crystals. We will also experimentally show that the voltage-frequency relation of the ac Josephson effect has to match the cavity resonance for successful emission.