Excitation of Trapped Modes in a Lattice of Dielectric Particles

An all-dielectric metasurface featuring resonant condition of the trapped mode excitation is considered. It is composed of a lattice of subwavelength particles made of high-refractive-index dielectric materials. These particles are structured in the form of disk having a round eccentric penetrating hole. Each particle in the lattice behaves as an individual all-dielectric resonator supporting a set of electric and magnetic modes. Since a particular asymmetry is introduced into the particles forming the lattice with respect to the electric field vector of the normally incident radiating wave, in addition to common electric and magnetic Mie-type resonances, the trapped mode with a high quality factor is excited. We involve the method of multipole expansion to reveal all peculiarities of the trapped mode excitation. Eventually, we observe and verify the excitation of the trapped mode in the microwave experiment.