School of Engineering, RMIT University, Melbourne, VIC, 3001, Australia.
Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument, Beijing Information Science & Technology University, Beijing, 100192, China.
Small. 2019 Mar;15(9):e1805251. doi: 10.1002/smll.201805251. Epub 2019 Jan 24.
Silicon photonics has demonstrated great potential in ultrasensitive biochemical sensing. However, it is challenging for such sensors to detect small ions which are also of great importance in many biochemical processes. A silicon photonic ion sensor enabled by an ionic dopant-driven plasmonic material is introduced here. The sensor consists of a microring resonator (MRR) coupled with a 2D restacked layer of near-infrared plasmonic molybdenum oxide. When the 2D plasmonic layer interacts with ions from the environment, a strong change in the refractive index results in a shift in the MRR resonance wavelength and simultaneously the alteration of plasmonic absorption leads to the modulation of MRR transmission power, hence generating dual sensing outputs which is unique to other optical ion sensors. Proof-of-concept via a pH sensing model is demonstrated, showing up to 7 orders improvement in sensitivity per unit area across the range from 1 to 13 compared to those of other optical pH sensors. This platform offers the unique potential for ultrasensitive and robust measurement of changes in ionic environment, generating new modalities for on-chip chemical sensors in the micro/nanoscale.
硅光子学在超灵敏生化传感方面表现出巨大的潜力。然而，对于这种传感器来说，检测小离子是具有挑战性的，因为小离子在许多生化过程中也非常重要。本文介绍了一种由离子掺杂驱动的等离子体材料实现的硅光子离子传感器。该传感器由一个微环谐振器 (MRR) 与二维堆叠的近红外等离子体氧化钼层耦合而成。当二维等离子体层与来自环境的离子相互作用时，折射率的强烈变化会导致 MRR 共振波长的移动，同时等离子体吸收的改变会导致 MRR 传输功率的调制，从而产生双传感输出，这是其他光学离子传感器所不具备的。通过 pH 传感模型进行了概念验证，与其他光学 pH 传感器相比，其在 1 到 13 的范围内的单位面积灵敏度提高了 7 个数量级。该平台为超灵敏和稳健的离子环境变化测量提供了独特的潜力，为微纳尺度上的片上化学传感器开辟了新的模式。
