Ultrasensitive sensing in air based on graphene-coated hollow core fibers

The mismatching between permittivities of guided mode and air limits the operation of accurately monitoring the change in the refractive index of the surrounding air. To solve it, we propose a platform using a hollow core fiber with the integration of graphene coating. Experimental results demonstrate that the anti-resonant reflecting guidance has been enhanced while it induces sharply and periodically lossy dips in the transmission spectrum. We conclude a sensitivity of −365.9 dB/RIU and a high detection limit of 2.73 × 10−6 RIU by means of interrogating the intensity of the lossy dips. We believe that this configuration opens a direction for highly sensitive sensing in researches of chemistry, medicine, and biology.