| Since the discovery of the quantum Hall effect,the topological phase of matter in solidstate electronic systems has developed rapidly.Subsequently,topological insulators were introduced into optical systems,giving rise to topological photonic crystals.In the field of topological photonics,the symmetry of photonic crystals(generally spatial inversion symmetry and temporal inversion symmetry)has been broken by various means to cause topological phase transitions in photonic crystals.In this dissertation,we introduce periodic disorder into a cellular photonic crystal with synchronously rotating dielectric pillars and observe whether such disorder destroys the topological phase of our photonic crystals.The simultaneous rotation of a dielectric pillars in a Kekulé lattice leads to a change in Dirac cone with its spatial inversion symmetry broken.During the rotation,an energy band inversion occurs and the parity of the eigen electric fields near Dirac points in the energy band diagram are reversed,thus triggering a topological phase transition.Based on this topological photonic crystal model a magnetic field of a certain strength is applied along transverse direction,and then Chern values corresponding to the energy bands are calculated.Inspired by the photonic topological Anderson insulator,we introduce periodic disorder in such a topological photonic crystal with synchronous rotation: one in the dielectric constant and the other in the rotation angle.The values of the dielectric constant and the rotation angle are generated randomly following Gaussian and uniform distributions.The Chern numbers are also calculated under such periodic disorders,so that Chern numbers are used to determine whether a topological phase transition occurs after introduction of disorder.Our results show that the introduction of disorder in a gyromagnetic material causes the topological phase to break down from non-trivial to trivial as the disorder strength increases. |
PDF Full Text Request