The permittivity and permeability behaviors of composites made from the multiwalled carbon nanotubes with magnetic impurity Ni and the wax have been studied in 3–18GHz. The unusual permittivity dispersion behaviors have been explained based on the Cole-Cole model and the conductivity contribution model. Permeability is found to have negative imaginary parts within 3–11GHz. The composites are found to show good microwave absorbing performances (reflection loss <−20dB): matching thickness is 1.5mm and absorbing frequency band is 11.6–12.4GHz, and the absorbing performance can be explained by the “geometrical effect.”

The mid-infrared (mid-IR) is a strategically important band for numerous applications ranging from night vision to biochemical sensing. Here we theoretically analyzed and experimentally realized a Huygens metasurface platform capable of fulfilling a diverse cross-section of optical functions in the mid-IR. The meta-optical elements were constructed using high-index chalcogenide films deposited on fluoride substrates: the choices of wide-band transparent materials allow the design to be scaled across a broad infrared spectrum. Capitalizing on a two-component Huygens’ meta-atom design, the meta-optical devices feature an ultra-thin profile (λ0/8 in thickness) and measured optical efficiencies up to 75% in transmissive mode for linearly polarized light, representing major improvements over state-of-the-art. We have also demonstrated mid-IR transmissive meta-lenses with diffraction-limited focusing and imaging performance. The projected size, weight and power advantages, coupled with the manufacturing scalability leveraging standard microfabrication technologies, make the Huygens meta-optical devices promising for next-generation mid-IR system applications.

To explore the resonance mechanism of nanocrystalline FeCoNi flake composites, characterization of the flakes was investigated. The structural and magnetic properties of flakes manifestly tailored the features of microwave permeability spectrum of flake composites, relating to the physical effects of nanograins. The exchange mode with a few modifications was used to explain the origin of composite microwave performance, and the computed results were close to the experiment. It is believed that the exchange energy, dominating in the microwave resonance of spherical nanoparticles, plays an equally important role in nanocrystalline flakes.