Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany.
Beilstein J Nanotechnol. 2012;3:674-83. doi: 10.3762/bjnano.3.77. Epub 2012 Oct 4.
Regular arrays of metallic nano-triangles - so called Fischer patterns - are fabricated by nano-sphere lithography. We studied such gold nano-triangle arrays on silicon or glass substrates. A series of different samples was investigated with a parabolic mirror based confocal microscope where the sample is scanned through the laser focus. By employing higher order laser modes (azimuthally and radially polarised laser beams), we can excite the Fischer patterns using either a pure in-plane (x,y) electric field or a strongly z-directional (optical axis of the optical microscope) electric field. We collected and evaluated the emitted luminescence and thereby investigated the respectively excited plasmonic modes. These varied considerably: firstly with the light polarisation in the focus, secondly with the aspect ratio of the triangles and thirdly with the employed substrate. Moreover, we obtained strongly enhanced Raman spectra of an adenine (sub-)monolayer on gold Fischer patterns on glass. We thus showed that gold Fischer patterns are promising surface-enhanced Raman scattering (SERS) substrates.
常规的金属纳米三角阵列 - 所谓的 Fischer 图案 - 通过纳米球光刻法制造。我们研究了硅或玻璃衬底上的这种金纳米三角阵列。通过抛物面镜共焦显微镜对一系列不同的样品进行了研究，其中通过激光焦点扫描样品。通过采用高阶激光模式（角向和径向偏振激光束），我们可以使用纯面内（x，y）电场或强 z 方向（光学显微镜的光轴）电场来激发 Fischer 图案。我们收集和评估了发射的荧光，从而研究了分别激发的等离子体模式。这些模式变化很大：首先是在焦点处的光偏振，其次是三角形的纵横比，第三是所使用的衬底。此外，我们还获得了在玻璃上的金 Fischer 图案上的腺嘌呤（亚）单层的强烈增强拉曼光谱。因此，我们表明金 Fischer 图案是有前途的表面增强拉曼散射（SERS）衬底。
