Quality factor enhancement in photonic crystal slabs by manipulation of the ring of exceptional points

Presently, we investigate the influence of the extent of a ring of exceptional points on the Q-factor of three-dimensional photonic crystal slabs. By changing the thickness of the slab, the extent of the ring of exceptional points is varied, allowing us to recover the Dirac cones in open, non-Hermitian systems. In this case, three bound states in the continuum are exhibited close to the Γ-point. For an optimized thickness of the slab, the associated Q-factors are found to grow rapidly with the size of the slab. The present results may lead to novel, small area and high Q-factor photonic crystal surface-emitting lasers.