title: Functional multi-band THz meta-foils.
abstract: In this paper, we present the first experimental demonstration of double- and triple-band negative refraction index meta-foils in the terahertz (THz) region. Multi-band meta-foils constructed by multi-cell S-string resonators in a single structure exhibit simultaneously negative permittivity and negative permeability responses at multiple frequencies. The phenomena are confirmed by numerical simulations and Fourier transform infrared spectroscopy measurements. The flexible, freestanding multi-band meta-foils provide a promising candidate for the development of multi-frequency THz materials and devices.
authors.affiliation: Center for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore, 2 Science Drive 3, 117542, Singapore.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Wu
authors.affiliation: Karlsruhe Institute of Technology (KIT), Network of Excellent Retired Scientists (NES) and Institute of Microstructure Technology (IMT), Postfach 3640, 76021 Karlsruhe, Germany.
authors.forename: Herbert O
authors.initials: HO
authors.lastname: Moser
authors.affiliation: The Electromagnetics Academy at Zhejiang University, Department of Information Science & Electronics Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Su
authors.initials: S
authors.lastname: Xu
authors.affiliation: Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, 117603, Singapore.
authors.forename: Linke
authors.initials: L
authors.lastname: Jian
authors.affiliation: Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, 117603, Singapore.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Banas
authors.affiliation: Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, 117603, Singapore.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Banas
authors.affiliation: The Electromagnetics Academy at Zhejiang University, Department of Information Science & Electronics Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Hongsheng
authors.initials: H
authors.lastname: Chen
authors.affiliation: Center for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore, 2 Science Drive 3, 117542, Singapore.
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Bettiol
authors.affiliation: 1] Center for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore, 2 Science Drive 3, 117542, Singapore [2] Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, 117603, Singapore.
authors.forename: Mark B H
authors.initials: MB
authors.lastname: Breese