Electromagnetic metamaterials opened the way to extraordinary manipulation of radiation. Terahertz (THz) and optical metamaterials are usually fabricated by traditional planar-patterning approaches, while the majority of practical applications require metamaterials with 3D resonators. Making arrays of precise 3D micro- and nanoresonators is still a challenging problem. Here we present a versatile set of approaches to fabrication of metamaterials with 3D resonators rolled-up from strained films, demonstrate novel THz metamaterials/systems, and show giant polarization rotation by several chiral metamaterials/systems. The polarization spectra of chiral metamaterials on semiconductor substrates exhibit ultrasharp quasiperiodic peaks. Application of 3D printing allowed assembling more complex systems, including the bianisotropic system with optimal microhelices, which showed an extreme polarization azimuth rotation of 85° with drop by 150° at a frequency shift of 0.4%. We refer the quasiperiodic peaks in the polarization spectra of metamaterial systems to the interplay of different resonances, including peculiar chiral waveguide resonance. Formed metamaterials cannot be made by any other presently available technology. All steps of presented fabrication approaches are parallel, IC-compatible and allow mass fabrication with scaling of rolled-up resonators up to visible frequencies. We anticipate that the rolled-up meta-atoms will be ideal building blocks for future generations of commercial metamaterials, devices and systems on their basis.

No abstract

No abstract

No abstract

In the present paper, a theoretical and experimental study of a highly absorptive, weakly reflective coating designed and fabricated on the basis of 3D THz resonant elements is reported. Transmission and reflection of electromagnetic waves from the metamaterial-substrate structure involving a highly absorptive, weakly reflective array of artificial bi-anisotropic elements were analyzed. The samples contained paired right-handed and left-handed helices, due to the fact that the chirality was compensated. The parameters of helices were optimized to achieve roughly identical values of dielectric permittivity and magnetic permeability. As a result, the metamaterial exhibited weak reflectivity in the vicinity of resonance frequency. On the other hand, effective resonance properties of the helices were tuned to ensure substantial absorption of THz radiation. Analytical expressions for the coefficients of radiation reflection and transmission in the samples were derived by solving a boundary-value problem for the propagation of electromagnetic waves in the metamaterial-substrate system. Simulated properties of fabricated structures were compared with experimental data.

No abstract

No abstract

No abstract