[13p-N321-1~15] 3.11 フォトニック構造・現象

▼ [13p-N321-4] Light transmission in triangular lattice photonic crystal waveguides with 120-degree sharp bends

〇Wei Dai¹、Taiki Yoda²、Yuto Moritake^1,3、Masaaki Ono^2,4、Eiichi Kuramochi^2,4、Masaya Notomi^1,2,4 (1.Tokyo Tech、2.NTT BRL、3.JST PRESTO、4.NTT NPC)

キーワード：photonic crystal, topological photonics

Valley photonic crystals (VPhCs) can be constructed by breaking the inversion symmetry of the bulk lattice. Two VPhCs connected by an interface, as a photonic crystal waveguide (PhCWG), can support valley-polarized states of light, which are reported to travel robustly through 120-degree sharp bends with suppressed corner reflection. Since the broken inversion symmetry is the heart of valley photonic properties, we compare the light transmission through 120-degree bends using PhCWGs with and without the inversion symmetry to investigate its influence. Surprisingly, we observed high transmission through 120-degree sharp bends in PhCWGs with the inversion symmetry. We found that the presence of the inversion symmetry does not cause significant differences in terms of the transmission through 120-degree bends. We report both the theoretical and the experimental results.