title: Electrically controllable terahertz square-loop metamaterial based on VO₂ thin film.
abstract: An electrically controllable square-loop metamaterial based on vanadium dioxide (VO2) thin film was proposed in the terahertz frequency regime. The square-loop shaped metamaterial was adopted to perform roles not only as a resonator but also as a micro-heater for the electrical control of the VO2. A dual-resonant square-loop structure was designed to realize band-pass characteristics in the desired frequency band. The measured Q-factors of the basic and scaled-down metamaterials fabricated on VO2 thin films were 2.22 and 1.61 at the center frequencies of 0.44 and 1.14 THz in the passbands, respectively. The transmittances of the proposed metamaterial were successfully controlled by applying a bias voltage without an external heater. The measured transmittance on-off ratios of the metamaterials were over 40 at the center frequencies in the passbands. In the future, electrically controllable terahertz metamaterial based on VO2 metamaterial could be employed as high-performance active filters or sensors.
authors.affiliation: THz Photonics Creative Research Center, Electronics and Telecommunications Research Institute, 218 Gajeong-ro, Yuseong-gu, Daejeon 305-700, Korea. School of Advanced Device Technology, University of Science & Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon 305-350, Korea.
authors.forename: Jun-Hwan
authors.initials: JH
authors.lastname: Shin
authors.forename: Kyung Hyun
authors.initials: KH
authors.lastname: Park
authors.forename: Han-Cheol
authors.initials: HC
authors.lastname: Ryu