On-chip ultra-compact hexagonal boron nitride topological ring-resonator in visible region

TL;DR

This paper introduces an ultra-compact topological ring-resonator based on hexagonal boron nitride that achieves robust unidirectional transmission in the visible spectrum, with high quality factor and design flexibility.

Contribution

It presents a novel topological photonic ring-resonator design using hBN VPC, demonstrating unidirectional edge states and high Q-factor in the visible range, advancing quantum photonic integration.

Findings

Achieved unidirectional transmission in the visible spectrum (600-650 nm).

Demonstrated high quality factor of 679.3 in the resonator.

Showed design flexibility with different shapes and configurations.

Abstract

Ultra-compact topological ring-resonators with chirality are important devices for quantum optics. However, there are limited demonstrations of chiral resonators, especially in the visible region. We proposed a topological photonic ring-resonator based on hexagonal boron nitride (hBN) valley photonic crystal (VPC). The spin-valley locking effect in VPC allows achieving robust unidirectional transmission of edge states in the visible region (600 nm-650 nm). As a result, a high quality factor (679.3) with a free spectral range of 15.2 nm in the visible region can be achieved in a hBN all-pass filter with a compact size. In addition, we investigated the transmission properties of hBN ring-resonators with different shapes and combinations, confirming the flexibility of designing topological ring-resonators based on this principle. This design can be readily integrated with quantum photonic chips for broad applications.