Quantum Nanoplasmonic Alchemy: Transforming Yttrium into an On-Chip Hydrogen Sensor

Abstract

We numerically demonstrate a nanoplasmonic hydrogen sensor based on a gold-yttrium-platinum plasmonic waveguide, utilizing Rigorous Coupled Wave Analysis (RCWA) to analyze its optical response. A thin yttrium layer, upon hydrogen absorption, undergoes a phase transition from metallic to semiconducting states at ambient conditions, altering its dielectric permittivity and reflectivity characteristics. These optical changes, observed in the presence and absence of hydrogen, enable the spectral interrogation-based sensing of different atomic ratios of hydrogen (H/Y). Our simulations reveal a plasmon resonance red-shift (Δλ) and enhanced differential reflectance (ΔR), confirming high detection sensitivity. The sensor’s response is further optimized by varying the waveguide height, air gap, and yttrium hydride thickness, demonstrating tunability across a broad spectral range. The findings establish yttrium hydride-based nanostructures as promising candidates for real-time hydrogen detection, with applications in energy storage, environmental monitoring, and industrial safety.