Searching for natural materials exhibiting larger electron-electron interactions constitutes a traditional approach to high temperature superconductivity research. Very recently we pointed out that the newly developed field of electromagnetic metamaterials deals with the somewhat related task of dielectric response engineering on a sub-100 nm scale. Considerable enhancement of the electron-electron interaction may be expected in such metamaterial scenarios as in epsilon near zero (ENZ) and hyperbolic metamaterials. In both cases dielectric function may become small and negative in substantial portions of the relevant four-momentum space, leading to enhancement of the electron pairing interaction. This approach has been verified in experiments with aluminium-based metamaterials. Metamaterial superconductor with Tc = 3.9 K have been fabricated, that is three times that of pure aluminium (Tc = 1.2 K), which opens up new possibilities to considerably improve Tc of other simple superconductors. Taking advantage of the demonstrated success of this approach, the critical temperature of hypothetic niobium, MgB2 and H2S-based metamaterial superconductors is evaluated. The MgB2-based metamaterial superconductors are projected to reach the liquid nitrogen temperature range. In the case of an H2S-based metamaterial projected Tc appears to reach ~250 K.
All-dielectric metamaterials composed of high index and low loss dielectric resonators have become a promising way for high-efficient optical devices. However, fabricating terahertz all-dielectric metamaterials and actively tuning their properties still remain challenges. In this paper, an effective method has been developed to prepare high-quality microspheres based all-dielectric metamaterial operating in terahertz (THz) range. Then, we propose a magnetically tunable THz all-dielectric metamaterial based on liquid crystal (LC). The all-dielectric metamaterial is immersed into LC and tuned by…
Electromagnetically induced transparency (EIT) analogue in all-dielectric metamaterials with a high quality factor provides an effective route to enhance light-matter interaction at the nanoscale. In particular, the active control applied to it enables great degree of freedom for spatial light modulation and thus promises functional device applications with high flexible tunability. Here we load graphene into all-dielectric metamaterials and realize the remarkably high modulation depth in the transmission amplitude of the EIT resonance with the manipulation of graphene conductivity, via shifti…
A planar all-dielectric metamaterial made of a double-periodic lattice whose unit cell consists of a single subwavelength dielectric particle having the form of a disk possessing a penetrating hole is considered. The resonant states in the transmitted spectra of the metamaterial are identified considering modes inherent to the individual cylindrical dielectric resonator. A correlation between the asymmetry in particle's geometry, which arises from the off-centered displacement of the hole, and formation of the Mie-type and trapped modes is established. The advantages of using a coaxial-sector …
Tunable dielectric meta-surface nanostructures offer incredible performance in optical application due to their extraordinary tunability of the polarization and engineering the dispersion of light with low loss in infrared range. In this article, we designed and experimentally measured the tunability of all-dielectric subwavelength silicon nanoparticles with the help of the temperature-based refractive index of the liquid crystal in the telecom regime. The proposed structure composed of high dielectric nanodisk surrounded by nematic liquid crystal (NLC) is simulated with numerical software, as…
Motivated by the theoretical observation that isotropic chirality can exist even in completely random systems, we design a dielectric metamaterial consisting of a random colloid of meta-atoms, which exhibits unprecedentedly high isotropic optical activity. Each meta-atom is composed of a helically arranged cluster of silicon nanospheres. Such clusters can be fabricated by large-scale DNA self-assembly techniques. It is demonstrated that the use of a high concentration of the meta-atoms in the colloid provides significant suppressions of incoherent scattering losses. As a result, the proposed s…
When the feature size of photonic structures becomes comparable or even smaller than the wavelength of light, the fabrication imperfections inevitably introduce disorder that may eliminate many functionalities of subwavelength photonic devices. Here we suggest a novel concept to achieve a robust bandgap which can endure disorder beyond 30 as a result of the transition from photonic crystals to Mie-resonant metamaterials. By utilizing Mie-resonant metamaterials with high refractive index, we demonstrate photonic waveguides and cavities with strong robustness to position disorder, thus providing…
Metamaterial approach is capable of drastically increasing the critical temperature, Tc, of composite metal-dielectric superconductors. Tripling of Tc was observed in bulk Al-Al2O3 core-shell metamaterials. A theoretical model based on the Maxwell-Garnett approximation provides a microscopic explanation of this effect in terms of electron-electron pairing mediated by a hybrid plasmon-phonon excitation. We report the first observation of this excitation in Al-Al2O3 core-shell metamaterials using inelastic neutron scattering. This result provides support for this novel mechanism of superconducti…
The use of metamaterial as a way to mitigate the negative effects of absorption in metals on the Purcell effect in metal-dielectric structures is investigated. A layered metal-dielectric structure is considered as an anisotropic medium in the long-wavelength limit. The dispersion of the surface plasmon appearing at the boundary between such a structure and a different dielectric material, as well as the position of the peak in the local density of states are studied for various combinations of materials and filling factors of the periodic structure. The calculated frequency dependence of the P…
High-index dielectric materials are in great demand for nanophotonic devices and applications, from ultrathin optical elements to metal-free sub-diffraction light confinement and waveguiding. Here we show that chalcogenide topological insulators are particularly apt candidates for dielectric nanophotonic architectures in the infrared spectral range by reporting metamaterial resonances in chalcogenide crystals sustained well inside the mid-infrared, choosing Bi$_2$Te$_3$ as case study within this family of materials. Strong resonant modulation of the incident electromagnetic field is achieved t…
From surface to volume plasmons in hyperbolic metamaterials: General existence conditions for bulk high-k waves in metal-dielectric and graphene-dielectric multilayers
Tuning the macroscopic dielectric response on demand holds potential for actively tunable metaphotonics and optical devices. In recent years, graphene has been extensively investigated as a tunable element in nanophotonics. Significant theoretical work has been devoted on the tuning the hyperbolic properties of graphene/dielectric heterostructures, however, until now, such a motif has not been demonstrated experimentally. Here we focus on a graphene/polaritonic dielectric metamaterial, with strong optical resonances arising from the polar response of the dielectric, which are, in general, diff…
We numerically propose an all-dielectric hybrid metamaterial (MM) to realize all-optical switch and logic gates in shortwave infrared (SWIR) band. Such MM consists of one silicon rod and one Ge2Sb2Te5 (GST) rod pair. Utilizing the transition from amorphous to crystalline state of GST, such MM can produce electromagnetically induced transparency (EIT) analogue with active control. Based on this, we realized all-optical switching at 1500 nm with a modulation depth 84%. Besides, three different logic gates, NOT, NOR and OR, can also be achieved in this device simultaneously. Thanks to the reversi…
We investigated numerically the electromagnetically induced transparency (EIT) behavior with the maximum Q factor is up to 28000 in a metal-dielectric metamaterial. It composed of two layers, a metallic strip as bright mode stacked above a dielectric rod as another bright mode. The coherent coupling between the broad electric dipole induced by the metal strip and the narrow toroidal dipole induced by the dielectric rod leads to the destructive interference, then introduces a transparency window. Interestingly, the EIT window could be effectively influenced by varying parameters of the two laye…
Ultra-compact, densely integrated optical components manufactured on a CMOS-foundry platform are highly desirable for optical information processing and electronic-photonic co-integration. However, the large spatial extent of evanescent waves arising from nanoscale confinement, ubiquitous in silicon photonic devices, causes significant cross-talk and scattering loss. Here, we demonstrate that anisotropic all-dielectric metamaterials open a new degree of freedom in total internal reflection to shorten the decay length of evanescent waves. We experimentally show the reduction of cross-talk by gr…
