Metamaterials and negative index materials III
16:40 Invited talk : Poynting theorem and its implication on the signs of the imaginary parts of the electromagnetic constitutive parameters in passive metamaterial.
O. M. Ramahi, B. Alavikia, A. Kabiri
University of Waterloo (Canada) Metamaterials have been found experimentally and theoretically to yield negative imaginary permittivity or permeability. This conclusion was deemed impossible or non-physical by many researchers based on fundamental entropy concepts. In this work, we show that basic intuitive assumptions about the positiveness of the imaginary part of passive metamaterial cannot be guaranteed by the Poynting Theorem. In fact, we show that passivity does not necessarily imply negative imaginary parts while maintain consistency with entropy principles.
17:00 : Tunable negative permeability in a three-dimensional superconducting metamaterial
Cihan Kurter (1),T. Lan (2),L. Sarychev (1),S. Anlage (1)
(1)Missouri University of Science and Technology (USA) , (2)University of Maryland (USA) We demonstrate a highly tunable, 3D metamaterial made of superconducting spiral resonators. The rf transmission of a single element of the metamaterial shows a fundamental resonance peak at 24.95 MHz that shifts to a 25 percent smaller frequency and becomes degenerate when a 3D array of such elements is created. The metamaterial shows an in-situ tunable narrow frequency band in which the real part of the effective permeability is negative over a wide range of temperature.
17:15 : A Phase Diagram and an Order Parameter for the Transitions between Photonic Crystals and All-Dielectric Metamaterials
M. Rybin, D. Filonov, K. Samusev, P. Belov, Yury Kivshar, Mikhail Limonov
ITMO University (Russia) Photonic crystals and all-dielectric metamaterials can be composed of the same type of structural elements, and they may differ only by material's permittivity and a filling factor. Here we introduce a concept of phase transitions between these two classes of artificial structures, demonstrate its underlying mechanism, and suggest a phase diagram that places both photonic crystals and metamaterials on a common parameter plane. Our theory is confirmed by experiments with a square lattice composed of cylinders.
17:30 : Gate-controlled Circular Dichroism in Graphene Chiral Metamaterials
Teun-Teun Kim (1),Hyeon-Don Kim (2),Hyun-Sung Park (2),Sang Soon Oh (3),Bumki Min (2),Shuang Zhang (1)
(1)University of Birmingham (United Kingdom) , (2)Korea Advanced Institute of Science and Technology (Korea) , (3)Imperial College London (United Kingdom) We demonstrate electric control of circular dichroism for terahertz waves by active tuning of the coupling between adjacent chiral metamolecules. By hybridizing gated single-layer graphene with a conjugated double Z metamaterial, we experimentally show that the transmission of left-handed circular polarized light can be effectively controlled without affecting that for the right handed circular polarized wave.
17:45 : Nanoantenna Coupled Quantum Dot Infrared Photodetectors
Giancarlo Cerulo, Yuriy Fedoryshyn, Valeria Liverini, Mattias Beck, Jerome Faist
ETH Zurich (Switzerland) We present the proof of principle of the enhancement of the responsivity of a quantum dot infrared photodetector (QDIP) by means of complementary split ring resonator(c-SRR) nanoantennae. The nanantennae, coupled to the QDs in the detector, yield an enhancement of the responsivity of almost one order of magnitude.