Multi-resonance enhanced photothermal synergistic fiber-optic Tamm plasmon polariton tip for high-sensitivity and rapid hydrogen detection

Accurate and real-time detection of hydrogen (H2) is essential for ensuring energy security. Fiber-optic H2 sensors are gaining attention for their integration and remote sensing capabilities. However, they face challenges, including complex fabrication processes and limited response times. Here, we propose a fiber-optic H2 sensing tip based on Tamm plasmon polariton (TPP) resonance, consisting of a multilayer metal/dielectric Bragg reflector deposited directly on the fiber end facet, simplifying the fabrication process. The fiber-optic TPP (FOTPP) tip exhibits both TPP and multiple Fabry-Perot (FP) resonances simultaneously, with the TPP employed for highly sensitive H2 detection. Compared to FP resonance, TPP exhibits more than twice the sensitivity under the same structural dimension without cavity geometry deformation. The excellent performance is attributed to alterations in phase-matching conditions, driven by changes in penetration depth of TPP. Furthermore, the FP mode is utilized to achieve an efficient photothermal effect to catalyze the reaction between H2 and the FOTPP structure. Consequently, the response and recovery speeds of the FOTPP tip under resonance-enhanced photothermal assistance are improved by 6.5 and 2.1 times, respectively. Our work offers a novel strategy for developing TPP-integrated fiber-optic tips, refines the theoretical framework of photothermal-assisted detection systems, and provides clear experimental evidence.