Universal sensitivity of propagating surface plasmon resonance in nanostructure arrays

A universal, geometry-independent sensitivity is derived by using a black box model of surface plasmon excitation for two-dimensional nanostructures. It is shown that the resonant wavelength of surface plasmons and dielectric property of interfacial materials dominate the sensitivity. Sensitivity data of nanostructure arrays, widely collected from independent research groups, comply well with our results. This analysis provides a conceptual and intuitive insight into the plasmonic sensing, covering various excitation arrangements under the same umbrella. The universal sensitivity offers a quantitative tool to evaluate and predict the performance of plasmonic sensors.