Exploring the application of Tamm plasmon resonance structures in fiber tips for remote hydrogen sensing

Hydrogen (H₂) is a promising alternative to fossil fuels. However, safety concerns need constant monitoring. Fiber optical sensors have become crucial in this field due to their capability for remote measurements. Traditional plasmonic techniques applied on optical fibers rely on expensive materials, which implies removing the fiber protection, and the optimized bands are outside the infrared spectral range preferred in optical communications. To address these challenges, this work presents an alternative plasmonic structure at the fiber tip of a single-mode fiber. The approach is based on Tamm Plasmon Resonance (TPR), which can be excited at normal incidence with depolarized light. Numerical results indicate that the numerical aperture of the fiber has minimal impact on the TPR band. Experimental results validate the possibility of this approach for H₂ detection, showing a wavelength shift of 8.5nm for 4 vol% H₂ with the TPR band centered around 1565nm. The sensor presents a response time of 29s and a reset time of 27s. These findings open new avenues in the development of plasmonic optical fiber sensors for H₂ sensing, as they enable the possibility of exciting plasmonic modes without removing the fiber’s cladding and with simple structures.