High-sensitivity surface plasmon resonance spectroscopy based on a metal nanoslit array

We have chemically modified metal nanoslit array surfaces with alkanethiol self-assembled monolayers and have characterized the resulting spectral shift of optical transmission. Adsorption of a self-assembled monolayer (1.5 nm thick) on a silver nanoslit array (slit width of 30-50 nm and grating period of 360 nm) is found to cause an 11 nm redshift of the main transmission peak. Strong confinement of optical fields in the narrow slit region allows sensitive transduction of surface modification into a shift of surface plasmon resonance wavelength. (c) 2006 American Institute of Physics.