A Micro Structure POF Relative Humidity Sensor Modified With Agarose Based on Surface Plasmon Resonance and Evanescent Wave Loss


A novel high sensitivity relative humidity (RH) sensor was proposed by using micro structure plastic optical fiber (POF) based on the surface plasmon resonance (SPR) effect and the evanescent wave (EW) loss. The micro structure was fabricated on the POF and coated with a gold layer and agarose, adopting the sputtering and dip-coating technique. These construction effects on the attenuation of power caused by the SPR effect and the EW loss were used to perform RH detections. The agarose’s different refractive indexes (RIs) caused fluctuations in the transmission power when the humidity increased. The demonstrated experimental results showed that the proposed sensor achieved a linear response from 20% RH to 80% RH with a high sensitivity of 0.595µW/%. The proposed sensor had the advantages of fast response and recovery. Furthermore, the temperature dependence and the repeatability test of the sensor were also performed.


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This work was funded by the Fund of Shanxi“133i” Project Key Subject Construction; National Science Foundation of Shanxi Province, China (Grant No. 201701D121065). This work is accomplished at the Science and Technology on Electronic Test & Measurement Laboratory, North University of China. The authors wish to thank the members of the Center for Micron and Nano research at the North University of China for the provision of technical support during the work.

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Correspondence to Wenyi Liu.

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Hu, Y., Ghaffar, A., Hou, Y. et al. A Micro Structure POF Relative Humidity Sensor Modified With Agarose Based on Surface Plasmon Resonance and Evanescent Wave Loss. Photonic Sens (2020). https://doi.org/10.1007/s13320-020-0603-4

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  • SPR
  • evanescent wave loss
  • agarose
  • RH sensor