J
John F. O'Hara
Researcher at Oklahoma State University–Stillwater
Publications - 162
Citations - 11041
John F. O'Hara is an academic researcher from Oklahoma State University–Stillwater. The author has contributed to research in topics: Terahertz radiation & Metamaterial. The author has an hindex of 39, co-authored 154 publications receiving 9750 citations. Previous affiliations of John F. O'Hara include Los Alamos National Laboratory & University of Sheffield.
Papers
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PatentDOI
Active terahertz metamaterial devices
TL;DR: An active metamaterial device capable of efficient real-time control and manipulation of terahertz radiation is demonstrated, which enables modulation of THz transmission by 50 per cent, an order of magnitude improvement over existing devices.
Journal ArticleDOI
An Overview of the Theory and Applications of Metasurfaces: The Two-Dimensional Equivalents of Metamaterials
Christopher L. Holloway,Edward F. Kuester,Joshua A. Gordon,John F. O'Hara,James C. Booth,David R. Smith +5 more
TL;DR: Metamaterials are typically engineered by arranging a set of small scatterers or apertures in a regular array throughout a region of space, thus obtaining some desirable bulk electromagnetic behavior as mentioned in this paper.
Journal ArticleDOI
Experimental demonstration of frequency-agile terahertz metamaterials
Hou-Tong Chen,John F. O'Hara,Abul Kalam Azad,Antoinette J. Taylor,Richard D. Averitt,David Shrekenhamer,Willie J. Padilla +6 more
TL;DR: In this paper, the authors demonstrate frequency-agile terahertz metamaterials operating in the far-infrared by incorporating semiconductors in critical regions of metallic split-ring resonators.
Proceedings ArticleDOI
Active Terahertz Metamaterial Devices
Hou-Tong Chen,John F. O'Hara,Abul Kalam Azad,David Shrekenhamer,Willie J. Padilla,Joshua M. O. Zide,Arthur C. Gossard,Richard D. Averitt,Antoinette J. Taylor +8 more
TL;DR: In this paper, the authors demonstrate THz metamaterials exhibiting either amplitude control via carrier injection or depletion in the active semiconductor substrate or frequency control via photoexcitation of carriers into active semiconducting materials incorporated into the sub-wavelength metammaterial structure.
Journal ArticleDOI
Thin-film sensing with planar terahertz metamaterials: sensitivity and limitations.
John F. O'Hara,Ranjan Singh,Igal Brener,Evgenya I. Smirnova,Jiaguang Han,Antoinette J. Taylor,Weili Zhang +6 more
TL;DR: The limiting effects of varying the thickness of a dielectric overlayer on planar double split-ring resonator (SRR) arrays are studied by terahertz time-domain spectroscopy and the bounds of resonance shifting are discussed.