Highly-sensitive chemical detection in the infrared regime using plasmonic gold nanocrosses

In this work, we report the design, fabrication, and characterization of gold nanocrosses for chemosensing purposes. The nanocrosses are designed to exhibit a localized surface plasmon resonance which is very sensitive to refractive index changes in the surrounding medium, resulting in sensitivity values of around 500-700 nm per refractive index unit at wavelengths around 1.4 mu m. We experimentally demonstrate the functionalization of the gold nanocrosses and the successful sensing of chemical monolayers. (C) 2011 American Institute of Physics. [doi:10.1063/1.3558916]