title: Magnetic hyperbolic optical metamaterials.
abstract: Strongly anisotropic media where the principal components of electric permittivity or magnetic permeability tensors have opposite signs are termed as hyperbolic media. Such media support propagating electromagnetic waves with extremely large wave vectors exhibiting unique optical properties. However, in all artificial and natural optical materials studied to date, the hyperbolic dispersion originates solely from the electric response. This restricts material functionality to one polarization of light and inhibits free-space impedance matching. Such restrictions can be overcome in media having components of opposite signs for both electric and magnetic tensors. Here we present the experimental demonstration of the magnetic hyperbolic dispersion in three-dimensional metamaterials. We measure metamaterial isofrequency contours and reveal the topological phase transition between the elliptic and hyperbolic dispersion. In the hyperbolic regime, we demonstrate the strong enhancement of thermal emission, which becomes directional, coherent and polarized. Our findings show the possibilities for realizing efficient impedance-matched hyperbolic media for unpolarized light.
authors.affiliation: Nonlinear Physics Center and Center for Ultrahigh Bandwidth Devices for Optical Systems (CUDOS), Research School of Physics and Engineering, The Australian National University, Canberra, Australian Capital Territory 2601, Australia.
authors.forename: Sergey S
authors.initials: SS
authors.lastname: Kruk
authors.affiliation: NSF Nanoscale Science and Engineering Center, University of California, Berkeley, California 94720, USA.
authors.forename: Zi Jing
authors.initials: ZJ
authors.lastname: Wong
authors.affiliation: Nonlinear Physics Center and Center for Ultrahigh Bandwidth Devices for Optical Systems (CUDOS), Research School of Physics and Engineering, The Australian National University, Canberra, Australian Capital Territory 2601, Australia.|Institute of Applied Physics, Abbe Center of Photonics, Friedrich-Schiller-Universität Jena, 07743 Jena, Germany.
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Pshenay-Severin
authors.affiliation: NSF Nanoscale Science and Engineering Center, University of California, Berkeley, California 94720, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: O'Brien
authors.affiliation: Nonlinear Physics Center and Center for Ultrahigh Bandwidth Devices for Optical Systems (CUDOS), Research School of Physics and Engineering, The Australian National University, Canberra, Australian Capital Territory 2601, Australia.
authors.forename: Dragomir N
authors.identifier: http://orcid.org/0000-0002-4508-8646
authors.initials: DN
authors.lastname: Neshev
authors.affiliation: Nonlinear Physics Center and Center for Ultrahigh Bandwidth Devices for Optical Systems (CUDOS), Research School of Physics and Engineering, The Australian National University, Canberra, Australian Capital Territory 2601, Australia.
authors.forename: Yuri S
authors.initials: YS
authors.lastname: Kivshar
authors.affiliation: NSF Nanoscale Science and Engineering Center, University of California, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.|Department of Physics, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
authors.forename: Xiang
authors.initials: X
authors.lastname: Zhang