TiO2 microsphere-based metamaterials exhibiting effective magnetic response in the terahertz regime

Abstract

Thin layers of all-dielectric metamaterials based on TiO 2 spherical particle resonators are investigated. A new method based on spray drying of dissolved nanoparticles is used in the fabrication process. Spectral footprints of electric and magnetic dipoles are reported numerically and through experimental tests. It is a promising step for the construction of novel three-dimensional isotropic metamaterials exhibiting desired electromagnetic properties for terahertz applications.

Magnetic response of planar dielectric rings

“…The ring's dimensions are chosen for the terahertz frequency range. The value e = 100 À i is typical for the high permittivity dielectrics, such as TiO 2 , used at the terahertz frequencies [15]. It is clear from Fig.…”

Axial magnetic resonances of rotationally symmetric high-permittivity dielectric particles of arbitrary shape

“…The physical origin of the strong magnetic response lies in the resonant excitation of a magnetic dipole mode with a circular displacement current in the particle [2]. The magnetic resonances of dielectric particles have been demonstrated experimentally in the gigahertz [4,5], terahertz [6,7], mid-infrared [8,9], and visible [10] spectral ranges.…”

Applicability of point-dipoles approximation to all-dielectric metamaterials

“…In addition, they have more degrees of freedom for tuning the resonance frequency by geometrical parameters than, for example, spheres, cubes or cylinders. Furthermore, they exhibit resonances on the THz frequencies [19][20][21][22], a very promising range for emerging applications. Appearing most frequently as periodical structures composed of subwavelength elements (the metamaterial lattice constant is on the order of λ/20 − λ/4), three-dimensional metamaterials are often treated as continuous media (the procedure referred to as homogenization) described by some effective parameters, e.g., permittivity ε, permeability μ, refractive index n, and impedance z, which simplifies their description.…”