Theory and Engineering Techniques in Metal Hydride Plasmonics for Hydrogen Sensing

Abstract

This thesis proposes three techniques in metal hydride plasmonics for instru- mentation and sensing applications, all of them are investigated and simulated by

computation. First, the Harmonic Minimization Method is introduced, along with an optimization strategy for plasmonic sensors based on diffraction gratings. This approach connects low-complexity formalisms with grating profiles that are more

amenable to fabrication using widely adopted methods, achieving an average com- putation time of only 8 seconds. Next, the Tunable Diode Laser Plasmonic Grating

Spectroscopy (TDLPGS) technique is presented, proposing a system architecture for portable plasmonic instrumentation suited for hydrogen sensing. This method leverages variable grating periodicity under hydrogen loading, and the effects of optical and mechanical variations on the metal hydride’s plasmonic properties are

thoroughly analyzed. Harmonic detection routines are applied to the reflectance sig- nal to enhance measurement precision. Finally, an Oxide/Metal/Hydride structure

is proposed for integration with D-shaped optical fibers to develop hydrogen sensing devices. The influence of each layer’s thickness is investigated, and an optimization routine is suggested to maximize sensitivity under specific fabrication constraints. The device performance is acessed through a series of computational experiments.