One-way Valley-locked waveguide with large channel achieved by all-dielectric Photonic Crystals

TL;DR

This paper introduces a novel all-dielectric photonic crystal waveguide with valley-locking that achieves unidirectional light transmission across a large, uniformly distributed channel, enhancing low-loss nonreciprocal photonic devices.

Contribution

It presents a new one-way valley-locked waveguide with a large transmission channel based on bulk modes, differing from topological edge modes, with 100% efficiency and uniform field distribution.

Findings

Achieves unidirectional transmission with a large, uniform channel.

Utilizes bulk valley-locked modes instead of topological edge states.

Enables low-loss, efficient nonreciprocal photonic devices.

Abstract

Nonreciprocity, which denotes the asymmetric or even unidirectional transmission of light, constitutes the cornerstone of modern photonic circuits. In the realm of photonic devices, it has been widely utilized in isolators, circulators and so on. Recent topology in artificial materials, an unprecedented degree of freedom, has been proposed to solve the effect of impurities on nonreciprocal transmission. However, in view of the bulk-edge correspondence, the spatial width of the transmission channel with uniform field distribution is quite narrow and needs further exploration. In this paper, we proposed a one-way valley-locked waveguide with a large channel in an all-dielectric photonic crystal. Quite different from the topological edge modes, the unidirectional property of our waveguide comes from the bulk modes with valley-lock, which can fully utilize the whole dimension of the structure with an efficiency of 100%. Additionally, the electrical field is uniformly distributed across the entire channel, which opens a new avenue for low-loss nonreciprocity devices.