All-angle broadband ENZ metamaterials

Abstract

A novel type of metamaterial is presented to produce broadband near-zero effective permittivity to a defined polarized probing electromagnetic wave with varying angles of incidence. The metamaterial has a uniaxial unit cell structure made up of symmetric periodic multilayer superlattices with a rotational symmetry about the polarization of the probing electromagnetic wave. The unit cell is rigorously constructed based on the Bergman–Milton spectral representation of the effective permittivity, and its electrodynamic properties are theoretically verified by the eigenmode analysis, the band structure, the dispersion relation, and the isofrequency contours. The eigenmode analysis illustrates that the unit cell can be effectively regarded as a photonic crystal or a waveguide according to the incidence direction of the probing electromagnetic wave, and either of them is of the dynamic microstructure related to the frequency, which results in a broadband response. Meanwhile, the band structure, the dispersion relation, and the isofrequency contours show that the unit cell has the near-zero effective permittivity at all angles of incidence of the specified polarized probing electromagnetic wave. Finally, the reflection/transmission/absorption spectra to the prescribed polarization probing electromagnetic wave vividly reveal the all-angle broadband near-zero effective permittivity property of the metamaterial.

Multiple linear-crossing metamaterials for directional refraction

“…Fortunately, based on the Bergman spectral representation of the effective permittivity, the step-like design has been successfully used in realizing the multi frequency nearzero effective permittivity (Sun et al, 2013). Very recently, the allangle broadband near-zero effective permittivity property also has been demonstrated in the symmetric step-like multilayer structure (Sun et al, 2022). Inspired by these pioneering works, in this section we propose the composite stepped multilayer structure to realize the MLCMM.…”

Precise one-to-one equivalent nanocircuit models for layered metamaterials

“…Besides the simple layered metamaterials, the lumped-element model can also be applied in more complicated layered microstructures. According to the authors' previous work [21], a unit cell of the broadband ENZ metamaterials is constructed as shown in figure 4 the plasma frequency ω p = 2π × 265 × 10 12 rad s −1 , and the damping factor γ = 2π × 20 × 10 12 rad s −1 [44].…”

“…More importantly, the layered metamaterials can be designed with a sophisticated microstructure to operate across a broad range of frequencies, e.g. the broadband absorber [13,14], the broadband epsilon-near-zero (ENZ) metamaterials [15][16][17][18][19][20][21], and others [22]. Inspired by metamaterials, metactronics [23], also named as metatronics [24], is promoted to develop new technologies with fantastical functions by fusing metamaterials with nanoelectronics and nanophotonics.…”

Multipole Excitations and Nonlocality in 1d Plasmonic Nanostructures

“…This choice is not accidental. It is motivated by the fact that this component can vary in wide limits, that gives rise to numerous potential applications [31][32][33][34].…”