Work

Self-rolled-up SiN x microtube with enhanced Q-factor and quasi-single-mode emission for label-free optical sensing

Year: 2026

Type: article

Abstract: In this study, we propose a self-rolled-up SiN x microtube with enhanced Q -factor and quasi-single-mode emission characteristics. Two types of microtubes are fabricated using standard CMOS-compatible microfabrication techniques: one directly on a Si substrate, and the other on a SiO 2 thin film. Compared to the microtube formed on SiO 2 , the microtube on the Si substrate exhibits stable quasi-single-mode emission due to strong optical coupling between the intrinsic emission peak and the cavity resonance. This enhanced coupling significantly increases the Q -factor, reaching up to 1062. When the microtube is immersed in water, the mismatch between the emission and resonance modes leads to a notable decrease in both emission intensity and Q -factor, indicating a high sensitivity to changes in the surrounding refractive index. Compared to the microtube-based sensing approaches that required mode identification and complex spectral analysis, this method enables label-free detection with clearly observable signal changes. These features make the self-rolled-up SiN x microtube a promising platform for optical sensing applications, offering high detection sensitivity, compact device integration, and label-free operation.

Source: Optics Express

DOI: 10.1364/oe.575354

Authors: Jiachen Liu, Yingying Zeng, Haifeng Hu, Xiaogang Chen, Qiwen Zhan

Institutions: University of Shanghai for Science and Technology, Shanghai Zhangjiang Laboratory, Zhangjiang Laboratory

Language: English

Topic: Photonic and Optical Devices

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,270

Funder: National Natural Science Foundation of China