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Terahertz Microfluidic Sensing Using a Parallel-plate Waveguide Sensor
Published on: August 30, 2012
Breaking the Bottleneck in Limit of Detection of Surface Refractive Index Sensing by Harnessing Meta-Waveguide
Wanxin Li1, Jiewen Li1, Rui Li1
1National Key Laboratory of Laser Spatial Information, Guangdong Provincial Key Laboratory of Integrated Photonic-Electronic Chip, Guangdong Provincial Key Laboratory of Aerospace Communication and Networking Technology, Harbin Institute of Technology, Harbin Institute of Technology campus, Xili University Town, Shenzhen, Guangdong, China.
Abstract:
Pushing sensor sensitivity to the extreme remains a central pursuit in sensing research. However, the limit of detection (LOD) is ultimately limited by the trade-off between intrinsic sensitivity and noise: improvements in sensitivity often introduce higher noise, yielding only marginal gains in LOD. Here, we leverage mode splitting in meta-waveguide microring resonators (MWMRs)-a typically overlooked phenomenon-to suppress drift-induced bias and noise without sacrificing interfacial refractive-index sensitivity. This approach reduces baseline drift to just 4.6 fm/min during representative measurements, enabling quantitative detection of ultra-weak surface perturbations. The sensing performance is validated through the streptavidin-biotin interaction, achieving reliable detection of 0.01 pg/mL streptavidin with a blank reference and a splitting noise of 1.3 pm. This reflection-induced mode splitting framework breaks the longstanding LOD bottleneck in surface refractometric sensing and establishes MWMRs as a robust, drift-immune platform for ultra-sensitive optical interrogation.
