City Research Online

Abstract

We report on the characterisation of relative humidity sensors based on fibre Bragg gratings coated with two hygroscopic materials: polyimide (PI) and graphene oxide (GO). In both cases, sensitivity and response time could be tuned by varying the coating thickness, but graphene oxide provided significantly higher sensitivity and a faster response time than polyimide: for PI-coated sensors, a 1 pm/% increase in sensitivity resulted in a 94 s increase in response time, whereas for GO-coated sensors, the same increase in sensitivity only cost an additional 1 s increase in response time. These results show that graphene oxide is a promising material for faster-responding humidity sensors that can maintain high sensitivity.

Publication Type:	Conference or Workshop Item (Paper)
Additional Information:	Copyright 2025 Society of Photo‑Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this publication for a fee or for commercial purposes, and modification of the contents of the publication are prohibited.
Publisher Keywords:	fibre optic sensors, relative humidity, fibre Bragg gratings, polyimide, graphene oxide, response time
Subjects:	T Technology > TJ Mechanical engineering and machinery T Technology > TK Electrical engineering. Electronics Nuclear engineering
Departments:	School of Science & Technology School of Science & Technology > Engineering
SWORD Depositor:	Symplectic Administrator

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