Tailoring the refractive index of impedance-matched ferrite composites.

Independent control of the magnetic and electric properties of two-part and three-part ferrite composites is demonstrated through variation of particle size and volume fraction of ferrite inclusions. This provides a route to creating broadband impedance-matched composites with tailored high refractive-index values. A two-part composite comprising NiZn ferrite in a PTFE dielectric host with approximately equal values of relative real permittivity and permeability up to 100 MHz is manufactured.

Artificial intelligence for photonics and photonic materials.

Artificial intelligence (AI) is the most important new methodology in scientific research since the adoption of quantum mechanics and it is providing exciting results in numerous fields of science and technology. In this review we summarize research and discuss future opportunities for AI in the domains of photonics, nanophotonics, plasmonics and photonic materials discovery, including metamaterials.

Nano- and Micro-Auxetic Plasmonic Materials.

Plasmonic nanostructures with a negative Poisson ratio are demonstrated, having the unusual mechanical property of auxetics to expand laterally when being stretched. Using nanomembrane technology, auxetics are shrunk by orders of magnitude, giving simultaneous access to optical properties of plasmonic metamaterials, as well as auxetic mechanical properties on the nanoscale.

Focused electromagnetic doughnut pulses and their interaction with interfaces and nanostructures.

"The "focused doughnut", a single-cycle electromagnetic perturbation of toroidal topology with inseparable time and spatial dependencies propagates at the speed of light in vacuum, as was shown by Hellwarth and Nouchi in 1996. While normal incidence reflection and refraction of conventional electromagnetic pulses in isotropic media do not lead to polarization changes, "focused doughnut" pulses undergo complex field transformations owing to the toroidal field structure and the presence of longitudinal components. We also demonstrate that "focused doughnuts" can interact strongly with structured media exciting dominant dynamic toroidal dipoles in spherical dielectric particles.