title: Near-field optical studies of local photomodification in nanostructured materials.
abstract: Fractal aggregates of silver nanoparticles are studied experimentally using atomic force microscopy and photon scanning tunnelling microscopy. Large changes in the near-field optical response of fractal aggregates are observed after the irradiation of samples with nanosecond laser pulses. The threshold energy density for photomodification using a 532 nm laser is measured to be 9 mJ cm(-2). It is shown that photomodification-induced changes in the local optical response can be two orders of magnitude larger than changes in far-field absorption.
authors.affiliation: Department of Physics, New Mexico State University, Las Cruces 88003, USA.
authors.forename: W D
authors.initials: WD
authors.lastname: Bragg
authors.forename: V P
authors.initials: VP
authors.lastname: Safonov
authors.forename: W
authors.initials: W
authors.lastname: Kim
authors.forename: K
authors.initials: K
authors.lastname: Banerjee
authors.forename: M R
authors.initials: MR
authors.lastname: Young
authors.forename: J G
authors.initials: JG
authors.lastname: Zhu
authors.forename: Z C
authors.initials: ZC
authors.lastname: Ying
authors.forename: R L
authors.initials: RL
authors.lastname: Armstrong
authors.forename: V M
authors.initials: VM
authors.lastname: Shalaev