title: Selective optical assembly of highly uniform nanoparticles by doughnut-shaped beams.
abstract: A highly efficient natural light-harvesting antenna has a ring-like structure consisting of dye molecules whose absorption band changes through selective evolutionary processes driven by external stimuli, i.e., sunlight depending on its territory and thermal fluctuations. Inspired by this fact, here, we experimentally and theoretically demonstrate the selective assembling of ring-like arrangements of many silver nanorods with particular shapes and orientations onto a substrate by the light-induced force of doughnut beams with different colours (wavelengths) and polarizations in conjunction with thermal fluctuations at room temperature. Furthermore, the majority of nanorods are electromagnetically coupled to form a prominent red-shifted collective mode of localized surface plasmons resonant with the wavelength of the irradiated light, where a spectral broadening also appears for the efficient broadband optical response. The discovered principle is a promising route for "bio-inspired selective optical assembly" of various nanomaterials that can be used in the wide field of nanotechnology.
authors.affiliation: 1] Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan [2] Center for Quantum Materials Science under Extreme Conditions, Osaka University, Toyonaka, Osaka 560-8531, Japan [3] PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Syoji
authors.initials: S
authors.lastname: Ito
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Yamauchi
authors.forename: Mamoru
authors.initials: M
authors.lastname: Tamura
authors.forename: Shimpei
authors.initials: S
authors.lastname: Hidaka
authors.forename: Hironori
authors.initials: H
authors.lastname: Hattori
authors.forename: Taichi
authors.initials: T
authors.lastname: Hamada
authors.forename: Keisuke
authors.initials: K
authors.lastname: Nishida
authors.forename: Shiho
authors.initials: S
authors.lastname: Tokonami
authors.forename: Tamitake
authors.initials: T
authors.lastname: Itoh
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Miyasaka
authors.forename: Takuya
authors.initials: T
authors.lastname: Iida