Development of optical field emitter arrays

Abstract

Optical field emitters are electron emission sources actuated by incident light. Optically actuated field emitters may produce ultrafast pulses of electrons when excited by ultrafast optical pulses, thus making them of interest for specific applications such as ultrafast electron microscopy, diffraction and spectroscopy; and as electron sources for X-ray generation. Recently proposed intense, coherent, and compact X-ray sources require low emittance, high brightness and short duration electron bunches that form a periodic pattern in the transverse plane. This thesis theoretically developed optical field emitter arrays that are suitable for use as the electron source for this novel X-ray source. Studies of several optical field emitter array structures, including vertically-standing gold nanopillars and silicon tips, in-plane gold nanostructures, and metallic line gratings, were performed via theoretical analysis and numerical simulations. Enhancement of the optical nearfield and power absorption was achieved by geometrical and plasmonic effects, leading to enhanced charge yield from the optical field emitter arrays.