Fig. 1. Schematic of lattice and Brillouin zone of common two-dimensional photonic crystals. (a) Square lattice; (b) triangular lattice; (c) honeycomb lattice

Fig. 2. Bandgap distribution map of triangular lattice. (a) Bandgap scanning map; (b) bandgap width

Fig. 3. Band structure and EFC of triangular lattice. (a) Band structure; (b) TE EFC for the first energy band

Fig. 4. Schematics of refraction at the interface. (a) From air to isotropic medium; (b) from air to PhC

Fig. 5. Steady light field distribution in PhC. (a) TE mode; (b) TM mode

Fig. 6. Steady light field distribution in PhC with oblique interface. (a) TE mode; (b) TM mode

Fig. 7. Influence of structural parameters on transmittance and reflectance. (a) Radius; (b) period

Fig. 8. Influence of the number of structural layers on polarization performance. (a) Transmittance and reflectance at oblique interface; (b) transmittance and reflectance at straight interface; (c) polarization extinction ratio

Fig. 9. Schematic of self-collimation. (a) Straight interface; (b) oblique interface

Fig. 10. TE EFC with higher precision. (a) EFC of the first energy band; (b) EFC near 0.5 frequency

Fig. 11. Variation in normalized transmittance with incident angle under different structures

Fig. 12. Steady light field with different structures and angles of incident light. (a) a/λ=0.5, θ=θ_b, oblique surface; (b) a/λ=0.54, θ=θ_b, straight surface; (c) a/λ=0.54, θ=θ_b, oblique surface; (d) a/λ=0.5, θ=θ_b+3°, oblique surface; (e) a/λ=0.54, θ=θ_b+3°, straight surface; (f) a/λ=0.54, θ=θ_b+3°, oblique surface; (g) a/λ=0.5, θ=15°, oblique surface; (h) a/λ=0.54, θ=15°, straight surface; (i) a/λ=0.54, θ=15°, oblique surface

Fig. 13. Variation in refractive group velocity and angle of refract light under different angles of incident light