Graphene oxide functionalized micro-tapered long-period fiber grating for sensitive heavy metal sensing

Abstract

We report a Ni2+ heavy metal sensor based on a graphene oxide (GO) functionalized micro-tapered long-period fiber grating (MTLPG) where light–matter interaction is enhanced. With high-quality GO coating on fiber with strong adhesion and controllable thickness, the GO-coated MTLPG demonstrated a resonant wavelength shift and intensity change, corresponding to a sensitivity of up to 5.12 × 10−4 nm ppb−1 and 3.07 × 10–4 dB ppb−1, respectively. Moreover, the limits of detection were 2.5 ppb and 0.27 ppb, respectively, operating in a wider concentration range of 1 ppb to 1 × 107 ppb. The proposed optical platform can be developed for superior chemical sensing applications.