Coupled-mode theory for plasmonic resonators integrated with silicon waveguides towards mid-infrared spectroscopic sensing
Coupled-mode theory for plasmonic resonators integrated with silicon waveguides towards mid-infrared spectroscopic sensing
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DOI：
10.1364/oe.28.002020
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发表时间：
2020-01-20
期刊：
影响因子：
3.8
通讯作者：
Li, Mo
中科院分区：
文献类型：
--
作者：
Chen, Che;Oh, Sang-Hyun;Li, Mo
中红外激光器、探测器和纳米纤维技术的进步使新的器件架构能够实现片上传感应用。特别地，等离子体共振器与介电波导的直接集成可以生成用于经由表面增强红外吸收（SEIRA）光谱进行生物化学感测的超紧凑器件架构。这种混合架构的理论研究是其优化势在必行。在这项工作中，我们使用时间耦合模理论和数值模拟研究等离子体共振器阵列和波导之间的耦合机制。结果表明，当谐振腔-波导耦合率最大时，波导的透射消光比达到最大值。此外，在引入与等离子体激元-波导系统耦合的振荡器形式的模型分析物之后，可以成功地拟合具有分析物吸收的透射曲线。我们得出结论，当分析物吸收频率与透射最小值相同时，提取的感测信号可以最大化，这与等离子体共振频率不同。这一结论与介质谐振器的情况相反，并为未来器件的设计优化和灵敏度提高提供了重要指导。(C)根据OSA开放获取出版协议的条款，2020年美国光学学会
Advances in mid-IR lasers, detectors, and nanofabrication technology have enabled new device architectures to implement on-chip sensing applications. In particular, direct integration of plasmonic resonators with a dielectric waveguide can generate an ultra-compact device architecture for biochemical sensing via surface-enhanced infrared absorption (SEIRA) spectroscopy. A theoretical investigation of such a hybrid architecture is imperative for its optimization. In this work, we investigate the coupling mechanism between a plasmonic resonator array and a waveguide using temporal coupled-mode theory and numerical simulation. The results conclude that the waveguide transmission extinction ratio reaches maxima when the resonator-waveguide coupling rate is maximal. Moreover, after introducing a model analyte in the form of an oscillator coupled with the plasmonics-waveguide system, the transmission curve with analyte absorption can be fitted successfully. We conclude that the extracted sensing signal can be maximized when analyte absorption frequency is the same as the transmission minima, which is different from the plasmonic resonance frequency. This conclusion is in contrast to the dielectric resonator scenario and provides an important guideline for design optimization and sensitivity improvement of future devices. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement