Fiber-Optic Hydrogen Leakage Sensor Based on Photonic-Nanojet-Assisted Gasochromic Effect

Hydrogen as a new energy has the advantage of zero carbon emissions. Replacing conventional fossil fuels with hydrogen is an emerging developing strategy for environmental protection worldwide. For safety assurance, gas leakage monitoring is required throughout the entire hydrogen industry chain. Particularly, long-term, online, and remote hydrogen detection is of great significance. This article proposes a new sensor that integrates photonic nanojet technology on optical fiber with the gasochromic effect. It has a large hydrogen concentration detection range of up to 100%, high repeatability with a relative standard deviation (RSD) of 0.3%, excellent gas selectivity, and fiber bending resistance. It exhibits a reflectance decreasing of 38.82% and a response time of 210 s for pure H2 at the most sensitive wavelength of 850 nm.