Chu Yizhuo, Zhu Wenqi, Wang Dongxing, Crozier Kenneth B
School of Engineering and Applied Sciences, Harvard University, 29 Oxford St. Cambridge, MA 02138, USA.
Opt Express. 2011 Oct 10;19(21):20054-68. doi: 10.1364/OE.19.020054.
The angular dependencies of the local field enhancement and the Raman emission enhancement are investigated, numerically and experimentally, for a plasmonic crystal double resonance SERS substrate consisting of a periodic array of gold disks above a gold film. We find that the local field enhancement is very sensitive to the incident angle. The Raman emission enhancement has a strong angular dependence on the detection direction, with the substrate "beaming" the Raman emission so that different Raman lines have different far-field patterns. We demonstrate that a stronger SERS signal results when the plasmonic substrate is illuminated with a collimated, rather than focused, laser beam.
针对由金膜上方的金盘周期性阵列构成的等离子体晶体双共振表面增强拉曼散射（SERS）基底，通过数值模拟和实验研究了局部场增强和拉曼发射增强的角度依赖性。我们发现局部场增强对入射角非常敏感。拉曼发射增强对检测方向有很强的角度依赖性，基底会“发射”拉曼发射，使得不同的拉曼谱线具有不同的远场模式。我们证明，当用准直激光束而非聚焦激光束照射等离子体基底时，会产生更强的SERS信号。
