Waveguide-Integrated Compact Plasmonic Resonators for On-Chip Mid-Infrared Laser Spectroscopy
Waveguide-Integrated Compact Plasmonic Resonators for On-Chip Mid-Infrared Laser Spectroscopy
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DOI：
10.1021/acs.nanolett.8b03156
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发表时间：
2018-12-01
期刊：
影响因子：
10.8
通讯作者：
Oh, Sang-Hyun
中科院分区：
文献类型：
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作者：
Chen, Che;Mohr, Daniel A.;Oh, Sang-Hyun
纳米等离子体器件与硅光子平台的集成，结合了等离子体的高场增强和介质波导的超低传播损耗，为高效光传输提供了新的途径。这种混合集成避免了对庞大的自由空间光学装置的需要，并可以导致完全集成的片上光学传感系统。在这里，我们展示了超紧凑等离子体谐振器，直接在硅波导上进行中红外光谱化学传感。等离子体纳米棒谐振器的占地面积只有2 μ m(2)，但它们可以有效地与中红外波导模式耦合。通过波导的透射谱直接测量等离子体共振，耦合效率大于70%，相对于倏逝波导场强的场强增强系数大于3600。利用该混合装置和可调谐中红外激光源，成功地展示了薄聚甲基丙烯酸甲酯薄膜和十八硫醇单层的表面增强红外吸收光谱。
The integration of nanoplasmonic devices with a silicon photonic platform affords a new approach for efficient light delivery by combining the high field enhancement of plasmonics and the ultralow propagation loss of dielectric waveguides. Such a hybrid integration obviates the need for a bulky free-space optics setup and can lead to fully integrated, on-chip optical sensing systems. Here, we demonstrate ultracompact plasmonic resonators directly patterned atop a silicon waveguide for mid-infrared spectroscopic chemical sensing. The footprint of the plasmonic nanorod resonators is as small as 2 mu m(2), yet they can couple with the mid-infrared waveguide mode efficiently. The plasmonic resonance is directly measured through the transmission spectrum of the waveguide with a coupling efficiency greater than 70% and a field intensity enhancement factor of over 3600 relative to the evanescent waveguide field intensity. Using this hybrid device and a tunable mid-infrared laser source, surface-enhanced infrared absorption spectroscopy of both a thin poly(methyl methacrylate) film and an octadecanethiol monolayer is successfully demonstrated.