Near-field optical studies of surface plasmons in single metal nanoparticles

Summary form only given.The near-field transmission spectra for a series of individual Au particles were taken. We find that the homogeneous linewidths and the spectral positions of the surface plasmon (SP) resonance vary slightly from particle to particle and thus are not always reproducible by application of Mie theory using bulk values for the dielectric function of Au. Surface scattering events and possibly also quantum size effects might contribute to the SP lineshape opening up the exciting possibility of sensoring the nano-environment of a single Au particle.