Broadband isotropic μ-near-zero metamaterials

Natural diamagnetism, while being a common phenomenon, is limited to permeability values close to unity. Artificial diamagnetics, to the contrary, can be engineered to provide much lower values and may even possess an effective permeability close to zero. In this letter, we provide an experimental confirmation of the possibility to obtain extremely low permeability values by manufacturing an isotropic metamaterial composed of conducting cubes. We show that the practical assembly is quite sensitive to fabrication tolerances and demonstrate that permeability of about μ=0.15 is realisable.This work was supported by the Ministry of Education and Science of Russian Federation (Project 11.G34.31.0020), Dynasty Foundation (Russia), grant of the President of Russian Federation, and by the Australian Research Council (CUDOS Centre of Excellence CE110001018)

Competing nonlinearities with metamaterials

We suggest an approach for creating metamaterials with sign-varying nonlinear response. We demonstrate that microwavemetamaterials with such competing nonlinearities can be created by loading split-ring resonators (“meta-atoms” of the structure) with pairs of varactor diodes and photodiodes exhibiting nonmonotonic resonance frequency shift with changing incident microwave power. Additionally, the nonlinear response of such metamaterials can be controlled by illuminating the meta-atoms by light.This work was supported by the Ministry of Education and Science of Russia, projects 11.G34.31.0020, 14.B37.21.1176 and 14.B37.21.1283, Scholarship of the President of the Russian Federation for young scientists and graduate students, Russian Foundation for Basic Research (RFBR), Dynasty Foundation (Russia) and the Australian Research Council (Australia)

Hyperbolic transmission-line metamaterials

We demonstrate how to realize an indefinite media with hyperbolic isofrequency surfaces in wavevector space by employing two-dimensional metamaterial transmission lines. We classify different types of such media, and visualize the peculiar character of wave propagation by study of the cross-like emission pattern of a current source placed in the lattice center. Our results are supported by a solution of the Kirchhoff equations, an analytical theory, and experimental data.The authors acknowledge a support from the Ministry of Education and Science of the Russian Federation, Russian. Foundation for Basic Research, Dynasty Foundation (Russia), the Engineering and Physical Sciences Research Council (UK), and the Australian Research Council (Australia)

Controlling split-ring resonators with light

We propose an original approach for creating tunable electromagnetic metamaterials. We demonstrate experimentally that magnetic resonance of a split-ring resonator (“meta-atom” of a composite material) with a photodiode operated in photovoltaic mode can be tuned by changing the intensity of an external light source. Moreover, for two coupled resonators, we show that we can achieve light-induced switching between dark- and bright-mode responses.The authors acknowledge a support from the Ministry of Education and Science of the Russian Federation, Dynasty Foundation (Russia), the Engineering and Physical Sciences Research Council (UK), and the Australian Research Council (Australia)

Bending of electromagnetic waves in all-dielectric particle array waveguides

We propose and demonstrate experimentally an alternative approach for realizing subwavelength photonic structures, exploiting the waveguiding properties of chains of high-index dielectric disks with both electric and magnetic dipole resonances. We reveal that the electromagnetic energy can be efficiently guided through sharp corners by means of the mode polarization conversion at waveguide bends. We confirm experimentally the guidance through a 90° bend in the microwave frequency range.This work was supported by the Ministry of Education and Science of the Russian Federation (Project 11.G34.31.0020, GOSZADANIE 2014/190, Zadanie No. 3.561.2014/K, 14.584.21.0009 10), by Russian Foundation for Basic Research, the Dynasty Foundation (Russia), the Australian Research Council via Future Fellowship Program (No. FT110100037), and the Australian National University

Fano resonances in antennas: General control over radiation patterns

The concepts of many optical devices are based on fundamental physical phenomena such as resonances. One of the commonly used devices is an electromagnetic antenna that converts localized energy into freely propagating radiation and vise versa, offering