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

Abstract

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 (1.5nm thick) on a silver nanoslit array (slit width of 30–50nm and grating period of 360nm) is found to cause an 11nm 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.