Estados de borda em cristais fotônicos topológicos

Abstract

Over the last few years, research on topological photonic crystals has received great prominence due to the possibility of simulating quantum phenomena and the possibility of technological implementation in devices where the information flux is done by light. Physicists and engineers have been looking for new systems that present topological behavior, as well as seeking to understand the characteristics of existing systems better. Topological photonic crystals are systems where the electromagnetic properties periodically change in space and the topological invariant is non-zero, this non-zero topological invariant can be achieved using perturbations in the system, and because of that, a topological phase is induced. Following this objective, we induce the topological phase in this thesis by introducing geometrical perturbations in different photonic crystals composed of dielectric rods. We study triangular lattices with punctual symmetry group C6, and we notice the perturbation opens a complete gap in the band structure of the systems. Also, some perturbation values lead the system to a non-trivial topological phase. Because of that, edge estates emerge inside the bandgap. Moreover, those edge states present pseudospin behavior and are protected by topology. Thus, they are well-localized and robust against defects and disorders. This robustness means that light transmitted through the interface composed of trivial and non-trivial photonic crystals will face defects with minimum energy losses, reflection, and flux changes, then it is creating a coherent channel for light dynamics.