title: Intensity tunable infrared broadband absorbers based on VO2 phase transition using planar layered thin films.
abstract: Plasmonic and metamaterial based nano/micro-structured materials enable spectrally selective resonant absorption, where the resonant bandwidth and absorption intensity can be engineered by controlling the size and geometry of nanostructures. Here, we demonstrate a simple, lithography-free approach for obtaining a resonant and dynamically tunable broadband absorber based on vanadium dioxide (VO2) phase transition. Using planar layered thin film structures, where top layer is chosen to be an ultrathin (20 nm) VO2 film, we demonstrate broadband IR light absorption tuning (from ~90% to ~30% in measured absorption) over the entire mid-wavelength infrared spectrum. Our numerical and experimental results indicate that the bandwidth of the absorption bands can be controlled by changing the dielectric spacer layer thickness. Broadband tunable absorbers can find applications in absorption filters, thermal emitters, thermophotovoltaics and sensing.
authors: Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, IL 60208, USA.|Department of Electrical Engineering, Turkish Military Academy, 06654 Ankara, Turkey.
authors: Hasan
authors: H
authors: Kocer
authors: Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, IL 60208, USA.
authors: Serkan
authors: S
authors: Butun
authors: Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, IL 60208, USA.
authors: Edgar
authors: E
authors: Palacios
authors: Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, IL 60208, USA.
authors: Zizhuo
authors: Z
authors: Liu
authors: School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ 85287, USA.
authors: Sefaattin
authors: S
authors: Tongay
authors: Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA 94720, USA.
authors: Deyi
authors: D
authors: Fu
authors: Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA 94720, USA.
authors: Kevin
authors: K
authors: Wang
authors: Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA 94720, USA.
authors: Junqiao
authors: J
authors: Wu
authors: Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, IL 60208, USA.
authors: Koray
authors: K
authors: Aydin