Improvement of Figure of Merit for Gold Nanobar Array Plasmonic Sensors
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- Ye, J. & Van Dorpe, P. Plasmonics (2011) 6: 665. doi:10.1007/s11468-011-9249-9
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We report a strategy to improve two types of the figure of merit (FOM and FOM*) of the refractive index sensitivity of a gold nanobar array localized surface plasmon resonance (LSPR) biosensor by simply placing it close to a thin gold film with a dielectric spacer. The thickness of the dielectric spacer determines the plasmon coupling strength between the gold nanobars and the gold film and consequently the FOM and FOM* of the biosensor. From our calculations, when the spacer thickness is 20 nm, the FOM and FOM* reach maximal (4.68 and 310, respectively) and the sensitivity remains at a high value of 600 nm per refractive index unit. This biosensor scheme is practically realizable, and this strategy is also potentially applicable to the LSPR biosensors with other geometries.