Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
Nano Lett. 2012 Jan 11;12(1):269-74. doi: 10.1021/nl2034915. Epub 2011 Dec 13.
This paper reports that arrays of three-dimensional (3D), bowtie-shaped Au nanoparticle dimers can exhibit extremely high nonlinear absorption. Near-field interactions across the gap of the 3D bowties at the localized surface plasmon resonance wavelengths resulted in an increase of more than 4 orders of magnitude in local field intensity. The imaginary part of the third-order nonlinear susceptibility (Im χ((3))) for the 3D bowtie arrays embedded in a dielectric material was measured to be 10(-4) esu, more than 2 orders of magnitude higher than reported for other metal nanoparticle-dielectric composites. Moreover, 3D dimers with increased nanoscale structure (such as folding) exhibited increased optical nonlinearity. These 3D nanoantennas can be used as critical elements for nanoscale nonlinear optical devices.
本文报道了由三维（3D）、蝴蝶结形状的金纳米粒子二聚体组成的阵列可以表现出极高的非线性吸收。在局域表面等离子体共振波长下，3D 蝴蝶结的间隙处的近场相互作用导致局部场强度增加了超过 4 个数量级。嵌入介电材料中的 3D 蝴蝶结阵列的三阶非线性磁化率虚部（Im χ((3))) 测量值为 10(-4) esu，比其他金属纳米粒子-介电复合材料报道的值高 2 个数量级以上。此外，具有增加的纳米级结构（如折叠）的 3D 二聚体表现出增加的光学非线性。这些 3D 纳米天线可用作纳米尺度非线性光学器件的关键元件。
