High-sensitivity fiber-optic humidity sensor based on microfiber overlaid with niobium disulfide

Humidity sensors by exploiting transition metal dichalcogenides have attracted enormous attention in various applications. Here, we demonstrate a high-sensitivity fiber-optic humidity sensor based on microfibers overlaid with niobium disulfide (NbS2). Our experimental results show that this type of humidity sensor has high sensitivity, and good repeatability and reversibility. In the RH range of 72–97%, a sensitivity of up to 1.05 dB/RH% and an excellent linearity correlation of 99.5% were achieved. The transmission spectrum of the humidity sensor indicates that this sensor has a wide wavelength detection range from 1530 to 1565 nm. We applied the sensor to monitor human breath with a fast response. We anticipate that the humidity sensor will be useful for the environmental monitoring, food production, and semiconductor industries.