This study presents an optical relative humidity (RH) sensor based on the hydrophilic feature of a polyvinyl alcohol (PVA) film and a phase-enhancement total-internal-reflection (TIR) heterodyne interferometer. The sensor operation is based on the interaction of a TIR evanescent wave with a PVA film coated on the base of a phase-enhancement TIR apparatus. Relative humidity influences the PVA refractive index, thus bringing a significant variation in the phase difference between the s- and p- polarized states of a beam completely reflected from the TIR apparatus. The phase difference variation can be obtained using heterodyne interferometric technique, and the relative humidity measurement therefore is realized. In this study, the sensor produced measurement sensitivity and resolution superior to 0.49°/% RH and 0.5% RH in the range of 30%–75% RH.

这项研究提出了一种基于聚乙烯醇（PVA）膜的亲水特性和相位增强的全内反射（TIR）外差干涉仪的光学相对湿度（RH）传感器。传感器的操作基于TIR van逝波与在相位增强TIR装置的基座上涂覆的PVA膜的相互作用。相对湿度会影响PVA折射率，因此会导致s-和p之间的相位差发生明显变化-从TIR设备完全反射的光束的偏振态。可以使用外差干涉测量技术获得相差变化，并因此实现相对湿度测量。在这项研究中，传感器在30％至75％RH的范围内产生了优于0.49°/％RH和0.5％RH的测量灵敏度和分辨率。