Broadband Asymmetric Transmission with Wide Spectral Tunability based on Substrate-Embedded Silicon Nanoring Arrays

TL;DR

This paper proposes a silicon nanoring array device that achieves broadband asymmetric light transmission in the near-infrared, with high transmissivity contrast and tunability across a wide spectral range for photonic applications.

Contribution

The work introduces a substrate-embedded silicon nanoring array design that provides a highly tunable, broadband asymmetric transmission effect in the near-infrared spectrum, advancing integrated photonic device capabilities.

Findings

Achieves broadband asymmetric transmission from 1750 to 2400 nm.

Maximum forward transmissivity of 0.98 and minimum backward transmissivity of 0.015.

Operational spectral range can be tuned from 890 to 3300 nm.

Abstract

In this work, we theoretically propose a broadband asymmetric transmission (AT) device based on periodic Si nanoring arrays embedded in a SiO2 substrate. Results indicate that the device achieves a remarkable broadband AT effect in the near-infrared region (1750-2400 nm), with forward transmissivity exceeding 0.8 (maximum of 0.98), backward transmissivity less than 0.15 (minimum of 0.015) and an isolation ratio (IR) reaching a maximum of 17.8 dB at 2280 nm. Furthermore, the transmissivity spectrum exhibits excellent scalability and tunability through uniform scaling of the structure, allowing the operational band to be tailored across a wide spectral range, from 890 to 3300 nm. This Si-based nanostructure offers a robust and flexible platform for applications in optical isolation, multi-channel sensing, and integrated photonic circuits.