Figure 1
From: Dirac directional emission in anisotropic zero refractive index photonic crystals
Semi-Dirac point in rhombic photonic crystal.
(a) Two dimensional band structure along four different directions: ΓX (ky = 0, black solid), ΓM (ky/kx = tan18o, gray solid), ΓK (ky/kx = tan54o, gray dash) and ΓY (kx = 0, black dash). Inset is the lattice diagram. (b) Semi-X Dirac cone near Γ point. The irreducible representations of eigenmodes are labeled. (c) Iso-frequency contours of the frequency slightly above the semi-Dirac point of fD = 0.5588 c/a. (d) Zoom-in plot of (c) to show elliptical profiles and single-mode feature within a small k region. (e) Iso-frequency contours of the frequency slightly below the semi-Dirac point, showing the hyperbolic profiles and multi-mode at high-k components. The colorbar represents the variation of frequency.
