G. Chumanov et al., UNUSUAL EXTINCTION SPECTRA OF NANOMETER-SIZED SILVER PARTICLES ARRANGED IN 2-DIMENSIONAL ARRAYS, Journal of physical chemistry, 100(13), 1996, pp. 5166-5168
Two-dimensional arrays of 1000 Angstrom silver particles were prepared
by adsorption from colloidal suspensions onto glass slides derivatize
d with (3-mercaptopropyl)trimethoxysilane. By variation of the concent
ration of the colloidal suspensions, slides with different interpartic
le distances were obtained, and their extinction spectra were measured
in water. A blue shift (up to 90 nm) and sharpening of the peak corre
sponding to the plasmon resonance was observed as the distance between
particles decreased to a value comparable to, or less than, their dia
meter. The angular dependence of the extinction spectra was studied fo
r s- and p-polarized light. The data are interpreted to result from co
herent coupling of the plasmon resonances in closely spaced silver par
ticles upon irradiation with light.