Generation of convergent light spot by surface plasmon manipulated Smith-Purcell radiation on Yagi-Uda nanoantenna arrays (Conference Presentation)

Abstract

An electron beam passing over metallic gratings can emit Smith-Purcell radiations (SPRs). The electron beam can also excite surface plasmons (SPs) on the metallic surface. Recently, the generation of convergent light beam by SP-manipulated SPRs on metallic chirped gratings has been explored. However, for the one-dimensional gratings, only the emission along the direction of gratings (i.e. the direction of electron beam) is convergent. Therefore, the emission pattern is a line instead of a spot. In this work, the electron beam passing through the arrays of Yagi-Uda nanoantenna for generation of convergent light spot based on SP-manipulated SPR is proposed and investigated by FDTD simulation. The convergent spots that are formed directly above the nanoantenna arrays with different wavelengths are demonstrated. The emission angles controlled by the structure parameters and electron beam energy are also examined. This work provides a way toward practical applications in the fields of optical imaging, holography, cryptography and tunable visible light source.