Enhanced optical sensitivity of molybdenum diselenide (MoSe₂) coated side polished fiber for humidity sensing

In this paper, a side-polished fiber (SPF) coated with molybdenum diselenide (MoSe₂) is proposed, and its characteristic of relative humidity (RH) sensing is investigated. It is found in the experiment that an enhancement in RH sensitivity (0.321 dB/%RH) can be achieved in a very wide RH range of 32%RH to 73%RH for the proposed MoSe₂ coated SPF (MoSe₂CSPF). It is also shown that the MoSe₂CSPF has a rapid response of 1s and recovery time of 4s, which makes the sensor capable of monitoring human breath. The experimental results suggest MoSe₂ has a promising potential in photonics applications such as all-fiber optic humidity sensing networks.