title: Beamed Raman: directional excitation and emission enhancement in a plasmonic crystal double resonance SERS substrate.
abstract: 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.
authors: School of Engineering and Applied Sciences, Harvard University, 29 Oxford St. Cambridge, MA 02138, USA.
authors: Yizhuo
authors: Y
authors: Chu
authors: Wenqi
authors: W
authors: Zhu
authors: Dongxing
authors: D
authors: Wang
authors: Kenneth B
authors: KB
authors: Crozier
mesh_terms: D000465:Algorithms; D003460:Crystallization; D060733:Electromagnetic Radiation; D004867:Equipment Design; D006046:Gold; D007834:Lasers; D053768:Metal Nanoparticles / Q000737:chemistry; D015233:Models, Statistical; D055095:Optics and Photonics; D012542:Scattering, Radiation; D013059:Spectrum Analysis, Raman / Q000379:methods*; D020349:Surface Plasmon Resonance / Q000379:methods*
chemical_list: D006046:Gold