title: Measurement of Scattering Nonlinearities from a Single Plasmonic Nanoparticle.
abstract: Plasmonics, which are based on the collective oscillation of electrons due to light excitation, involve strongly enhanced local electric fields and thus have potential applications in nonlinear optics, which requires extraordinary optical intensity. One of the most studied nonlinearities in plasmonics is nonlinear absorption, including saturation and reverse saturation behaviors. Although scattering and absorption in nanoparticles are closely correlated by the Mie theory, there has been no report of nonlinearities in plasmonic scattering until very recently. Last year, not only saturation, but also reverse saturation of scattering in an isolated plasmonic particle was demonstrated for the first time. The results showed that saturable scattering exhibits clear wavelength dependence, which seems to be directly linked to the localized surface plasmon resonance (LSPR). Combined with the intensity-dependent measurements, the results suggest the possibility of a common mechanism underlying the nonlinear behaviors of scattering and absorption. These nonlinearities of scattering from a single gold nanosphere (GNS) are widely applicable, including in super-resolution microscopy and optical switches. In this paper, it is described in detail how to measure nonlinearity of scattering in a single GNP and how to employ the super-resolution technique to enhance the optical imaging resolution based on saturable scattering. This discovery features the first super-resolution microscopy based on nonlinear scattering, which is a novel non-bleaching contrast method that can achieve a resolution as low as l/8 and will potentially be useful in biomedicine and material studies.
authors.affiliation: Department of Physics, National Taiwan University.
authors.forename: Hsuan
authors.initials: H
authors.lastname: Lee
authors.affiliation: Department of Physics, National Taiwan University.
authors.forename: Kuan-Yu
authors.initials: KY
authors.lastname: Li
authors.affiliation: Department of Physics, National Taiwan University.
authors.forename: Yen-Ta
authors.initials: YT
authors.lastname: Huang
authors.affiliation: Department of Physics, National Taiwan University.
authors.forename: Po-Ting
authors.initials: PT
authors.lastname: Shen
authors.affiliation: Department of Physics, National Taiwan University.
authors.forename: Gitanjal
authors.initials: G
authors.lastname: Deka
authors.affiliation: Department of Applied Physics, Osaka University.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Oketani
authors.affiliation: Department of Applied Physics, Osaka University.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Yonemaru
authors.affiliation: Department of Applied Physics, Osaka University.
authors.forename: Masahito
authors.initials: M
authors.lastname: Yamanaka
authors.affiliation: Department of Applied Physics, Osaka University.
authors.forename: Katsumasa
authors.initials: K
authors.lastname: Fujita
authors.affiliation: Department of Physics, National Taiwan University; Molecular Imaging Center, National Taiwan University; swchu@ntu.edu.tw.
authors.forename: Shi-Wei
authors.initials: SW
authors.lastname: Chu
mesh_terms: D004583:Electrons; D006046:Gold / Q000737:chemistry*; D008027:Light; D053768:Metal Nanoparticles / Q000737:chemistry*; D017711:Nonlinear Dynamics; D061848:Optical Imaging / Q000379:methods; D055095:Optics and Photonics; D012542:Scattering, Radiation; D020349:Surface Plasmon Resonance / Q000379:methods*
chemical_list: D006046:Gold