Trapped mode control in metasurfaces composed of particles with the form birefringence property.

Progress in developing advanced photonic devices relies on introducing new materials, discovered physical principles, and optimal designs when constructing their components. Optical systems operating on the principles of excitation of extremely high-quality factor trapped modes (also known as the bound states in the continuum, BICs) are of great interest since they allow the implementation of laser and sensor devices with outstanding characteristics. In this paper, we discuss how one can utilize the anisotropic properties of novel materials (transition metal dichalcogenides, TMDs), particularly, the bulk molybdenum disulfide (MoS), to realize the excitation of trapped modes in dielectric metasurfaces.

Multi-band orbital angular momentum mode-division multiplexing by a compact set of microstrip ring-shaped resonator antenna.

Optical beams carrying orbital angular momentum (OAM) have received much attention due to the prospects of their use in terahertz communications, biomedical engineering, and imaging. Here we propose an antenna design for the generation of multiple beams carrying OAM with different topological states at the same frequency. The proposed OAM generator is based on a compact set of microstrip ring-shaped resonators.

Approach to analysis of all-dielectric free-form antenna systems.

The analytical model is proposed for simulation of the near-field and far-field characteristics of an all-dielectric free-form antenna system. The antenna system is constructed of an array of high-refractive-index dielectric resonators. The model relies on the coupled mode theory and the perturbation theory for the Maxwell's equations.

Multiple invisibility regions induced by symmetry breaking in a trimer of subwavelength graphene-coated nanowires.

Electromagnetic response is studied for clusters of subwavelength graphene-coated nanowires illuminated by a linearly polarized plane wave in the terahertz frequency range. The solution of the scattering problem is obtained with the Lorenz-Mie theory and multiple cylinder scattering formalism. The results show that normalized scattering cross-sections of nanowire clusters can be drastically changed by the symmetry breaking introduced into the cluster's design.

Bi-hyperbolic isofrequency surface in a magnetic-semiconductor superlattice.

The topology of isofrequency surfaces of a magnetic-semiconductor superlattice influenced by an external static magnetic field is studied. In particular, in the given structure, topology transitions from standard closed forms of spheres and ellipsoids to open ones of Type I and Type II hyperboloids as well as bi-hyperboloids were revealed and analyzed. In the latter case, it is found out that a complex of an ellipsoid and bi-hyperboloid in isofrequency surfaces appears as a simultaneous effect of both the ratio between magnetic and semiconductor filling factors and magnetic field influence.

Dispersion regions overlapping for bulk and surface polaritons in a magnetic-semiconductor superlattice.

Extraordinary dispersion features of both bulk and surface polaritons in a finely stratified magnetic-semiconductor structure which is influenced by an external static magnetic field in the Voigt geometry are discussed in this Letter. It is shown that the conditions for total overlapping dispersion regions for the simultaneous existence of bulk and surface polaritons can be reached, providing a conscious choice for the constitutive parameters and material fractions for both magnetic and semiconductor subsystems.