Evolution of accidental degenerate Dirac point in 2D photonic crystals

In this paper, the evolution of accidental degenerate Dirac points in two-dimensional photonic crystals (PCs) is studied. By adjusting the structural parameters of the PC, a series of new Dirac points can be obtained. The fitting formula describing the relationship between the parameters of the Dirac points is given, and the corresponding functional relationship between the frequency of Dirac points and the structural parameters can also be obtained. We further find that there is no corresponding Dirac point in the “inverted” structure. It is believed that this new discovery will provide an important guidance for practical application