TY - GEN
T1 - Nanofilm-coated long-period fiber grating humidity sensors for corrosion detection in structural health monitoring
AU - Zheng, Shijie
AU - Zhu, Yinian
AU - Krishnaswamy, Sridhar
PY - 2011
Y1 - 2011
N2 - Long-period gratings (LPGs) have shown their significant promising applications in sensors owing to the attractive features that they posses such as small size, immunity for electromagnetic interference, geometric versatility, multiplexing capability, and resistance to corrosive and hazardous environments. Recent researches have revealed that LPGs written on the standard optical fibers could be used as a powerful sensing platform for structural health monitoring. In this work, we inscribe LPGs into SMF-28 optical fiber by focused-beam CO2 laser, demonstrating as a refractive index sensor for nondestructive chemical detections in the civil infrastructures. Although evanescent-field based LPG sensors have been applied in quantitatively monitoring chemical analytes including moisture, chloride, and corrosion by-product, etc., the sensitivity, selectivity, and response time as well as thermo-stability of such sensors are still the issues for some special purposes. In order to improve those characteristics of the sensors, we propose two types of nano-film to be coated in grating region by electrostatic self-assembly (ESA) deposition processing. The primary coating does not affect on LPG transmission parameters such as resonance wavelength and its intensity that can be used for sensing, but it increases the sensitivity to refractive index change of surrounding material. The secondary coating is for selectively absorption of analyte molecule of interest. Response time of the nanofilm-coated LPG sensor is dependent on the analyte absorption and de-absorption rates as well as the thicknesses of the coating materials, which is also investigated. Multi-channel sensor system is being designed to monitor different analytes simultaneously, which is continuing to further explore the monitoring of structural health conditions through in situ measurements of corrosion in the concrete structures.
AB - Long-period gratings (LPGs) have shown their significant promising applications in sensors owing to the attractive features that they posses such as small size, immunity for electromagnetic interference, geometric versatility, multiplexing capability, and resistance to corrosive and hazardous environments. Recent researches have revealed that LPGs written on the standard optical fibers could be used as a powerful sensing platform for structural health monitoring. In this work, we inscribe LPGs into SMF-28 optical fiber by focused-beam CO2 laser, demonstrating as a refractive index sensor for nondestructive chemical detections in the civil infrastructures. Although evanescent-field based LPG sensors have been applied in quantitatively monitoring chemical analytes including moisture, chloride, and corrosion by-product, etc., the sensitivity, selectivity, and response time as well as thermo-stability of such sensors are still the issues for some special purposes. In order to improve those characteristics of the sensors, we propose two types of nano-film to be coated in grating region by electrostatic self-assembly (ESA) deposition processing. The primary coating does not affect on LPG transmission parameters such as resonance wavelength and its intensity that can be used for sensing, but it increases the sensitivity to refractive index change of surrounding material. The secondary coating is for selectively absorption of analyte molecule of interest. Response time of the nanofilm-coated LPG sensor is dependent on the analyte absorption and de-absorption rates as well as the thicknesses of the coating materials, which is also investigated. Multi-channel sensor system is being designed to monitor different analytes simultaneously, which is continuing to further explore the monitoring of structural health conditions through in situ measurements of corrosion in the concrete structures.
KW - Long-period gratings
KW - electrostatic self-assembly
KW - fiber Bragg grating
KW - fiber optic sensors
KW - nanostructure coating
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U2 - 10.1117/12.880478
DO - 10.1117/12.880478
M3 - Conference contribution
AN - SCOPUS:79956201475
SN - 9780819485458
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - Nondestructive Characterization for Composite Materials, Aerospace Engineering, Civil Infrastructure, and Homeland Security 2011
T2 - Nondestructive Characterization for Composite Materials, Aerospace Engineering, Civil Infrastructure, and Homeland Security 2011
Y2 - 7 March 2011 through 10 March 2011
ER -