Angular Dependence of Cathodoluminescence of Linear and Circular Au Gratings: Imaging the Coupling Angles between Surface Plasmon Polaritons and Light

• Published in: Journal of physical chemistry. C Vol. 118; no. 40; pp. 23247 - 23255
• Main Authors: Ma, X, Grüßer, M, Schuster, R
• Format: Journal Article
• Language: English
• Published: American Chemical Society 09-10-2014
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp506918p

We measured the wavelength-dependent angular light distribution upon cathodoluminescence of micrometer-sized linear and circular gold gratings to study the coupling of surface plasmon polaritons (SPP) to light. A point source of SPP was excited next to the gratings with an electron beam of a scanning electron microscope. Subsequent scattering of propagating SPP at the gratings led to emission of light. The observed angular emission pattern, i.e., the azimuthal and polar angles of the emitted light, could be well-explained within a simple model, considering momentum conservation upon the scattering process with the grating wave vector. Whereas the angular distribution of the emitted light was dependent on both grating period and shape, the spectral distribution was not significantly affected. Focusing of light coupled from SPP by sectors of circular gratings and narrow linear grating structures was also demonstrated.