Advancements of Intense Terahertz Field Focusing on Metallic Nanoarchitectures for Monitoring Hidden Interatomic Gas-Matter Interactions

With the advancements of nanotechnology, innovative photonic designs coupled with functional materials provide a unique way to acquire, share, and respond effectively to information. It is found that the simple deposition of a 30 nm-thick palladium nanofilm on a terahertz (THz) metasurface chip with a 14 nm-wide effective nanogap of asymmetric materials and geometries allows the tracking of both interatomic and interfacial gas-matter interactions, including gas adsorption, hydrogenation (or dehydrogenation), metal phase changes, and unique water-forming reactions. Combinatorial analyses by simulation and experimental measurements demonstrate the distinct nanostructures, which leads to significant light-matter interactions and corresponding THz absorption in a real-time, highly repeatable, and reliable manner. The complex lattice dynamics and intrinsic properties of metals influenced by hydrogen gas exposure are also thoroughly examined using systematically controlled ternary gas mixture devices that mimic normal temperature and pressure. Furthermore, the novel degrees of freedom are utilized to analyze various physical phenomena, and thus, analytical methods that enable the tracking of unknown hidden stages of water-forming reactions resulting in water growth are introduced. A single exposure of the wave spectrum emphasizes the robustness of the proposed THz nanoscopic probe, bridging the gap between fundamental laboratory research and industry. The proposed terahertz (THz) methodology enables the real-time tracking of interatomic and interfacial gas-matter interactions, gas adsorption, hydrogenation, metal phase changes, and water-forming reactions in the resonance frequency and transmittance domains. Robust THz nanoscopic probes reveal the underlying pathway and lattice dynamics inside the hidden stage of palladium during hydrogen/oxygen exposure and the subsequent catalytic reaction.image