Palladium adjoined gold split-ring resonators: A prospective nanoplasmonic hydrogen sensor

Herein we propose a nanoplasmonic hydrogen-sensor based on a composite geometry: gold nanosplit-ring in contact with a palladium-nanostructure. Our three-dimensional numerical simulations revealed a dipolar-plasmon resonance at 1274 nm in the far-field extinction spectra, which was shown to be sensitive to hydrogen concentration. The dipolar-plasmon resonance exhibited systematic red-shift with increase in hydrogen concentration over a range of three orders of magnitude, and this variation was fitted to a logarithmic function. The proposed geometry neither contains nanoscale-gap nor sharp-edges which is advantageous for nanofabrication. Such sensitive, single nano-composite plasmonic detection platforms can be harnessed for on-chip plasmonic sensors.