指向性
等离子体子
材料科学
响应度
光学
天线(收音机)
折射率
光电子学
物理
电信
光电探测器
计算机科学
作者
Bei Wu,Yuanhao Lou,Dan Wu,Qiuhong Min,Xinchen Wan,Hongyuan Zhang,Yarong Yu,Jian Ma,Gangzheng Si,Yuanjie Pang
出处
期刊:Nano Letters
[American Chemical Society]
日期:2022-03-14
卷期号:22 (6): 2374-2380
被引量:3
标识
DOI:10.1021/acs.nanolett.1c04949
摘要
In situ refractive index sensors integrated with nanoaperture-based optical tweezers possess stable and sensitive responsivity to single nanoparticles. In most existing works, detection events are only identified using the total light intensity with directivity information ignored, leading to a low signal-to-noise ratio. Here, we propose to detect an optically trapped 20 nm silica particle by monitoring directivity of a plasmonic antenna. The main and secondary radiation lobes of the antenna reverse upon trapping because the particle-induced perturbation negates the relative phase between two antenna elements, leading to a significant change of the antenna front-to-back ratio. As a result, we obtain a signal-to-noise ratio of 20, with an order-of-magnitude improvement as compared to the intensity-only detection scheme.
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