Investigating Nonreciprocal Topological Edge State and Chirality in a Nonlinear Photonic Metasurface

Photonic topological insulators and self-induced nonreciprocity in nonlinear media offer robust pathways toward advancing quantum information and integrated photonic technologies [1-2]. Our study merges these concepts, presenting a photonic crystal design based on two different all-dielectric checkerboard structures that form a topological interface. Linear optical response of this photonic crystal system shows a narrowband leaky mode and an accompanying topological edge state. The photonic crystal system is engineered by incorporating the Kerr nonlinearity and introducing both dielectric and air defects. An increase in the input beam intensity exploits the Kerr effect, resulting in spectral tunability and nonreciprocity in the transmission spectra. Our passive photonic crystal design addresses a key constraint of Kerr-based nonreciprocal devices: dynamic reciprocity. Our structure inherently maintains its nonreciprocal response over a relatively broad range of input intensities. The development of such nonreciprocal and nonlinear metasurfaces offers a significant advancement for quantum photonics.

Hafezi, M., et al., Nat. Photon. 7.12, 2013

Khanikaev, A. B., et al., Nat.Mater. 12.3, 2013