Fig. 3: Simulated optical vortex and anti-vortex modes in C5 symmetric photonic disclination cavities.
From: Vortex nanolaser based on a photonic disclination cavity
3D FEM simulation results for C5 symmetric photonic disclination cavities with expanded and shrunken cores in slab structures. The C4 symmetric bulk lattice is used to create these photonic disclination cavities with the following parameters: a = 500 nm, r0 = 0.18a, d0 = 0.54a and h = 275 nm, where a, r0, d0 and h are the lattice constant, radius of the air hole, centre-to-hole distance and slab thickness, respectively (Extended Data Fig. 5). The refractive index of the slab is 3.33. a, Photonic disclination cavity with expanded core. The air holes of the core are located 0.28a away from the centre. The red dashed pentagon denotes the disclination boundary. b, Calculated eigenmode frequencies (top) and Q factors (bottom) for the cavity of a. The red dot represents the resonant mode within the photonic bandgap (orange shaded area). c, Optical vortex mode excited in the cavity of a. The Hz field (left), polarization vector field (upper right) and phase distribution (lower right) represent the vortex feature of q = +1. d, Photonic disclination cavity with shrunken core. The air-hole positions in the core differ by 71 nm from those in the expanded core. The red dashed pentagon denotes the disclination boundary. e, Calculated eigenmode frequencies (top) and Q factors (bottom) for the cavity in d. The red dots represent the doubly degenerate modes within the photonic bandgap (orange shaded area). f,g, Optical anti-vortex modes excited in the cavity of d. The Hz field (left), polarization vector field (upper right) and phase distribution (lower right) represent the anti-vortex feature of q = −1. h,i, Calculated frequencies (h) and Q factors (i) of the vortex (black dots) and anti-vortex (red dots) modes as a function of Δ, the centre-to-centre distance between air holes in the expanded and shrunken cores (inset of h). The black and red circles indicate the values of Δ for the cavities in a and d, respectively.
