A. Tsiatmas

Temperature control of Fano resonances and transmission in superconducting metamaterials.

Losses are the main evil that limits the use of metamaterials in practical applications. While radiation losses may be controlled by design, Joule losses are hereditary to the metamaterial structures. An exception is superconducting metamaterials, where Joule losses can be uniquely controlled with temperature in a very wide range. We put this in use by demonstrating temperature-dependent transmission in the millimeter-wave part of the spectrum in high-Tc superconducting cuprate metamaterials supporting sub-radiant resonances of Fano type.We demonstrate a millimeter-wave range metamaterial fabricated from cuprate superconductor. Two complementary metamaterial structures have been studied, which exhibit Fano resonances emerging from the collective excitation of interacting magnetic and electric dipole modes.

Superconducting plasmonics and extraordinary transmission

Negative dielectric constant and dominant kinetic resistance make superconductors intriguing plasmonic media. Here we report on the effect of extraordinary transmission through an array of sub-wavelength holes in a perforated film of high-temperature YBCO superconductor.

Flux Exclusion Superconducting Quantum Metamaterial: Towards Quantum-level Switching

Nonlinear and switchable metamaterials achieved by artificial structuring on the subwavelength scale have become a central topic in photonics research. Switching with only a few quanta of excitation per metamolecule, metamaterials elementary building block, is the ultimate goal, achieving which will open new opportunities for energy efficient signal handling and quantum information processing. Recently, arrays of Josephson junction devices have been proposed as a possible solution. However, they require extremely high levels of nanofabrication. Here we introduce a new quantum superconducting metamaterial which exploits the magnetic flux quantization for switching. It does not contain Josephson junctions, making it simple to fabricate and scale into large arrays. The metamaterial was manufactured from a high-temperature superconductor and characterized in the low intensity regime, providing the first observation of the quantum phenomenon of flux exclusion affecting the far-field electromagnetic properties of the metamaterial.

Low-loss terahertz superconducting plasmonics

In the plasmonic regime, an electromagnetic wave bounded to the surface of a conductor can be confined to a region much smaller than its wavelength in free space. A major problem of plasmonic technology, however, is associated with large losses that these surface modes exhibit, intimately linked to Ohmic resistance of metals. In this work, we show that due to their dominant kinetic inductance, superconductors are intriguing yet natural plasmonic media capable of supporting low-loss plasmon waves with extreme confinement and the potential to serve as information carriers in compact terahertz data processing circuits.

Optical generation of intense ultrashort magnetic pulses at the nanoscale

Generating, controlling and sensing strong magnetic fields at ever shorter time and length scales is important for both fundamental solid-state physicsandtechnologicalapplicationssuchas magneticdatarecording.Here,we propose a scheme for producing strong ultrashort magnetic pulses localized at the nanoscale. We show that a bimetallic nanoring illuminated by femtosecond laser pulses responds with transient thermoelectric currents of picosecond duration, which in turn induce Tesla-scale magnetic fields in the ring cavity. Our method provides a practical way of generating intense nanoscale magnetic fields with great potential for materials characterization, terahertz radiation generation and data storage applications.

Superconducting analogue of optical plasmonic waveguides

We demonstrate a direct analogy between electromagnetic properties of superconductors at frequencies up to 6 THz (superconducting gap) and plasmonic metals in the optical part of the spectrum. We also identify the existence of a surface bound mode in superconducting waveguide structures, “superconducting plasmon”, that closely connected to surface plasmon polaritons in the noble metals. This is a peculiar low-frequency, low-loss mode that can be guided for tens of centimetres and confined on the scale of just few tens of nanometres, demonstrating an incredible application potential.

Optical excitation of unipolar tesla magnetic pulses in plasmonic nanostructures

The study of ultrafast magnetic phenomena underpinning the development of data storage technologies requires increasingly high spatial and temporal resolution. However, to date there is no easily accessible method that meets these criteria. Here we introduce a plasmonic source that allows for direct generation of unipolar, sub-ps, Tesla-scale magnetic pulses localized at the nanoscale.

Flux exclusion quantum superconducting metamaterial

The new type of metamaterial exploits magnetic flux quantization as a source of its nonlinear response but does not require Josephson junctions. We fabricated metamaterial from a high-Tc superconductor and report its electromagnetic characterization.