Near field images of an Ag nanoshell. Nanoshell exposed to (a) 721 nm, (b) 492 nm, and (c) 336 nm laser beam and consequential dipole, quadrupole, and dark plasmons, respectively. Surface plasmon oscillations are collective electron motion resultant of optical illumination, and subsequent modes are shown. Adapted from .
Kherlopian et al. BMC Systems Biology 2008 2:74 doi:10.1186/1752-0509-2-74