A Micro Structure POF Relative Humidity Sensor Modified With Agarose Based on Surface Plasmon Resonance and Evanescent W
- PDF / 1,076,719 Bytes
- 10 Pages / 595.22 x 842 pts (A4) Page_size
- 48 Downloads / 160 Views
A Micro Structure POF Relative Humidity Sensor Modified With Agarose Based on Surface Plasmon Resonance and Evanescent Wave Loss Yanjun HU, Abdul GHAFFAR, Yulong HOU, Wenyi LIU*, Fei LI, and Jun WANG Science and Technology on Electronic Test & Measurement Laboratory, North University of China, Taiyuan 030051, China *
Corresponding author: Wenyi LIU
E-mail: [email protected]
Abstract: 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 0.595 µW/%. 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. Keywords: SPR; evanescent wave loss; agarose; RH sensor Citation: Yanjun HU, Abdul GHAFFAR, Yulong HOU, Wenyi LIU, Fei LI, and Jun WANG, “A Micro Structure POF Relative Humidity Sensor Modified With Agarose Based on Surface Plasmon Resonance and Evanescent Wave Loss,” Photonic Sensors, DOI: 10.1007/s13320-020-0603-4.
1. Introduction Relative humidity (RH) attracts lots of attention, from agriculture, medicine, and other fields [1–3]. Fiber optic RH sensors have been researched widely due to the advantages of miniaturization and electromagnetic immunity. According to the sensor’s working principle, fiber optic RH sensors are categorized into gratings, interferometers, modal interferometers, loss mode resonances (LMRs), and optical absorption [4]. Gratings have unique spectral characteristics, combined with different hydrophilic materials,
which increase the system’s stability and sensitivity [5–9]. However, these sensors are cross-sensitive to temperature and strain, limiting the measurement accuracy. Model interference RH sensors such as photonic crystal fiber (PCF) [10], multi-segment splicing [11], and tapered fiber [12] have attracted attention owing to special structures. However, this type of fiber has the disadvantages of high price and low robustness, which increases the difficulty of sensor fabrication and system construction. The LMR occurs to the fiber and the coating, and the dielectric constant of the coating is required to be positive [4]. Many materials such as SnO2 [13, 14],
Received: 25 March 2020 / Revised: 1 August 2020 © The Author(s) 2020. This article is published with open access at Springerlink.com DOI: 10.1007/s13320-020-0603-4 Article type: Regular
Photonic Sensors
TiO2 [15], polycycli
Data Loading...
