摘要
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.
源语言 | 英语 |
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页(从-至) | 5515-5518 |
页数 | 4 |
期刊 | Optics Letters |
卷 | 41 |
期 | 23 |
DOI | |
出版状态 | 已出版 - 1 12月 2016 |