Lossless and loss-induced topological transitions of isofrequency surfaces in a biaxial gyroelectromagnetic medium

Abstract

Topological transitions of isofrequency surfaces of a composite magnetic-semiconductor structure influenced by an external static magnetic field are studied in the long-wavelength approximation. For the lossless case, the topological transitions of isofrequency surfaces from a closed ellipsoid to open Type I and Type II hyperboloids as well as a bi-hyperboloid are demonstrated. Conditions for critical points where the topological transitions occur are found out. It is revealed that actual material losses in the constituents of the composite medium strongly influence the dispersion behaviours for the extraordinary waves, which manifest themselves in the loss-induced topological transitions of isofrequency surfaces. It is shown that the loss-induced topological transitions from a Type I hyperboloid to a bi-hyperboloid appear in the frequency band where the real part of a particular principal component of the anisotropic constitutive parameter (permittivity or permeability tensor) is a near-zero value while its imaginary part is a non-zero value.arXiv:1811.07106v1 [cond-mat.mes-hall]

Topologically Protected and Highly Localized Surface Waves in Gyro‐Electromagnetic Metamaterials

“…Therefore, z is a constant and independent of frequency. [36][37][38][39][40] We analyze topological phases in the electromagnetic duality metamaterial model, which can be expressed as = . [10,[41][42][43] The corresponding medium can be implemented by using a periodic multi-layered structure of magnetic and semiconductor layers.…”

“…[10,[41][42][43] The corresponding medium can be implemented by using a periodic multi-layered structure of magnetic and semiconductor layers. [37][38][39][40] If the layers are thin enough, we can treat the whole system as a single anisotropic medium. The effective constitutive parameters then can be obtained by using the effective medium theory.…”

“…[38] The loss-induced topological transitions in a biaxial gyroelectromagnetic metamaterial were also found. [39] The gyroelectric response may be caused by the free carriers of the plasma driven by the magnetic (Lorentz) force, [25,38] and the gyromagnetic response is generally caused by the precession of the magnetic dipole around the axis determined by the bias field. [38] In this work, we study the surface waves and their topologically protected propagation on the surface of the gyro-electromagnetic metamaterials.…”

“…The gyro‐electromagnetic system simultaneously possesses nonzero gyrotropic elements in the permittivity and permeability tensors, which can bring a number of unique dispersion features. [ 36–40 ] The optical scattering anomalies under the protection of parity, time inversion, and duality operators are reported recently. [ 38 ] The loss‐induced topological transitions in a biaxial gyro‐electromagnetic metamaterial were also found.…”

Optical properties of PMMA inverse opal structures with anisotropic geometries by stretching

“…The microstructures of metamaterials have developed from double-split ring, single-split ring, and u-shaped ring to fishnet and double bars. Hyperbolic metamaterials are one of the nanophotonic structures relied on the indefinite permittivity, which is a specific high anisotropic dielectric properties [19][20][21][22][23]. They also have several advantages such as low loss, wider response angle, and frequency range.…”