Study of Surface Plasmon by Electron Beam Induced Light Emission Technique

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In the present research, we have developed the electron beam induced light emission technique using a light detection systems combined with a transmission electron microscope. This technique enables us to measure an emission spectrum with choosing a polarization direction, and observe a monochromatic photon map at a proper wavelength. Surface plasmon on metallic nano-structures can be visualized by this technique. The purpose of the present research is to investigate physical properties of surface plasmon on metallic nano-structures with sub-wavelength periods and to find a mechanism of them. We improved the previous cathodoluminescence detection system, introducing a CCD detector to measure an emission spectrum with a high sensitivity. The set-up for angular resolved measurement has also been developed. Samples are a stripe structure and their 1D array, 2D array of metal particles and metal films with nano-hole arrays. Several emission peaks were observed to appear in the emission spectra from those structures irradiated by an electron beam. Those peaks correspond to resonant modes of the localized surface plasmon (LSP) and standing wave modes of surface plasmon polariton (SPP) in the periodic structures. From the result of angular resolved measurements of spectrum image taken by scanning the electron beam, it was found that the interference between the transition radiation and surface plasmon induced radiation mainly causes the contrast in the photon maps. New information was also obtained in the study of the electron beam induced emission from photonic crystals and Smith-Purcell radiation from a periodic metal surface under the surface parallel electron beam illumination.