title: Near-field optical effect of a core-shell nanostructure in proximity to a flat surface.
abstract: We provide an analytical solution for studying the near-field optical effect of a core-shell nanostructure in proximity to a flat surface, within quasi-static approximation. The distribution of electrostatic potential and the field enhancement in this complex geometry are obtained by solving a set of linear equations. This analytical result can be applied to a wide range of systems associated with near-field optics and surface plasmon polaritons. To illustrate the power of this technique, we study the field-attenuation effect of an oxidized shell in a silver tip in a near-field scanning microscope. The thickness of oxidized layer can be monitored by measuring the intensity of light. We also find a linear relation between resonant frequency and temperature in an Ag-Au core-shell structure, which provides insight for local temperature detection with nm scale resolution. Our results also show good agreement with recent finite element method results.
authors: Department of Physics, University of Bonn, 53113 Bonn, Germany.
authors: Wenping
authors: W
authors: Cui
authors: Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors: Mingda
authors: M
authors: Li
authors: Department of Physics and State Key Laboratory of Low-Dimension Quantum Physics, Tsinghua University, Beijing 100084, China.
authors: Zuyang
authors: Z
authors: Dai
authors: Department of Condensed Matter Physics, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors: Qingping
authors: Q
authors: Meng
authors: Department of Condensed Matter Physics, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors: Yimei
authors: Y
authors: Zhu