title: Quadrupole mode in the extinction and elastic-scattering spectra of gold microstructures.
abstract: The quadrupole mode and the retardation-broadened, wavelength-shifted dipole mode have been observed in the extinction and elastic-scattering spectra of two-dimensional arrays of Au microstructures immersed in air, water, and toluene. The electron-beam lithographically produced Au microstructures, resembling hemispheres with radius ~100 nm, were arranged in a square lattice with a center-to-center separation of 500 nm and situated on a 5-nm-thick layer of Cr coated on an optically flat quartz substrate.
authors.forename: W P
authors.initials: WP
authors.lastname: Acker
authors.forename: B
authors.initials: B
authors.lastname: Schlicht
authors.forename: R K
authors.initials: RK
authors.lastname: Chang
authors.forename: P W
authors.initials: PW
authors.lastname: Barber