Experimental demonstration of topological slow light waveguides in valley photonic crystals

Abstract

We experimentally demonstrate topological slow light waveguides in valley photonic crystals (VPhCs). We employed a bearded interface formed between two topologically-distinct VPhCs patterned in an air-bridged silicon slab. The interface supports both topological and non-topological slow light modes below the light line. By means of optical microscopy, we observed light propagation in the topological mode in the slow light regime with a group index $n_{\mathrm{g}}$ over $30$. Furthermore, we confirmed light transmission via the slow light mode even under the presence of sharp waveguide bends. In comparison between the topological and non-topological modes, we found that the topological mode exhibits much more efficient waveguiding than the trivial one, elucidating topological protection in the slow light regime. This work paves the way for exploring topological slow-light devices compatible with existing photonics technologies.

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Cited by in corpus (10)

• Observation of strong backscattering in valley-Hall photonic topological interface modes
• A brief review of topological photonics in one, two, and three dimensions
• Topologically-protected single-photon sources with topological slow light photonic crystal waveguides
• A chiral topological add-drop filter for integrated quantum photonic circuits
• Optimizing the chiral Purcell factor for unidirectional single photon emitters in topological photonic crystal waveguides using inverse design
• High Transmission in 120-degree Sharp Bends of Inversion-symmetric and Inversion-asymmetric Photonic Crystal Waveguides
• Observation of slow light in glide-symmetric photonic-crystal waveguides
• Valley photonic crystal waveguides fabricated with CMOS-compatible process
• Asymmetric Chiral Coupling in a Topological Resonator
• EP restoration and fast-light edge states in photonic crystal waveguide with glide and time reversal symmetry