Anisotropic excitation of surface plasmon polaritons on a metal film by a scattering-type scanning near-field microscope with a non-rotationally-symmetric probe tip
Anisotropic excitation of surface plasmon polaritons on a metal film by a scattering-type scanning near-field microscope with a non-rotationally-symmetric probe tip
复制标题
通过具有非旋转对称探针尖端的散射型扫描近场显微镜对金属膜上表面等离子体激元的各向异性激发
DOI：
10.1515/nanoph-2017-0042
复制
发表时间：
2017
期刊：
影响因子：
7.5
通讯作者：
H. Roskos
中科院分区：
文献类型：
--
作者：
F. Walla;M. Wiecha;Nicolas Mecklenbeck;S. Beldi;F. Keilmann;M. Thomson;H. Roskos
用散射式扫描近场光学显微镜的金属化探头尖端研究了表面等离子体激元在金膜上的激发。在近红外激光照射下，针尖发射的极化子是各向异性的，并非如文献所预期的那样是圆对称的。此外，我们还通过从尖端反射的光确定了另一个激发通道，并激发了金属膜边缘的等离子体激元。虽然我们的结果是针对非旋转对称类型的探针尖端获得的，因此是这种情况下所特有的，但我们的结果表明，当使用S-近场光学显微镜研究等离子体结构时，必须考虑表面波的无意激发和各向异性表面波的传播，以便正确地解释等离子体激元产生和传播的特征。
Abstract We investigated the excitation of surface plasmon polaritons on gold films with the metallized probe tip of a scattering-type scanning near-field optical microscope (s-SNOM). The emission of the polaritons from the tip, illuminated by near-infrared laser radiation, was found to be anisotropic and not circularly symmetric as expected on the basis of literature data. We furthermore identified an additional excitation channel via light that was reflected off the tip and excited the plasmon polaritons at the edge of the metal film. Our results, while obtained for a non-rotationally-symmetric type of probe tip and thus specific for this situation, indicate that when an s-SNOM is employed for the investigation of plasmonic structures, the unintentional excitation of surface waves and anisotropic surface wave propagation must be considered in order to correctly interpret the signatures of plasmon polariton generation and propagation.