Abstract
We demonstrate a high-performance relative humidity (RH) sensor by coating a photonic crystal (PC) cavity with polyvinyl alcohol (PVA). Because a PC cavity’s evanescent field strongly interacts with the coated moisture-sensitive PVA film, the resonant wavelength is modified remarkably under varying RH levels ranging from 30% to 90%. In a PC cavity coated with a 720 nm thick PVA, the sensor exhibits a linear spectrum sensitivity exceeding 129 pm/%RH over 40–90%RH, and the power interrogation presents a high sensitivity as 0.77 dB/%RH. The resolvable humidity variation could be much less than 0.1%RH. Relying on the sub-micron thick PVA, the sensor promises a response time less than 300 ms and good repeatability. The dependence of the sensor performances on the PVA thickness is studied as well, indicating a tradeoff between the sensing dynamic range and the response time.
© 2016 Optical Society of America
Full Article | PDF ArticleMore Like This
Suroor L. Khashin, Saif A. Mohammed, and Hanan J. Taher
Opt. Continuum 1(11) 2308-2318 (2022)
Guofeng Yan, Yanhong Liang, El-Hang Lee, and Sailing He
Opt. Express 23(12) 15624-15634 (2015)
Yuqing Sun, Jiachen Guo, Yinfeng Xiao, Junfeng Fan, Jigang Chen, Dong Zhao, and Bo Jia
Appl. Opt. 61(22) 6658-6663 (2022)