Imaging Light with Photoelectrons on the Nano-Femto Scale

1.0 Introduction ............................................................................................................................. 1 1.1 Collective Electron Oscillations ..................................................................................... 2 1.1.1 Plasma Model ...................................................................................................... 2 1.1.2 Localized Surface Plasmons (LSPs) .................................................................. 4 1.1.3 Surface Plasmon Polaritons (SPPs) ................................................................... 7 1.2 Techniques of Imaging Plasmon Related Phenomena .............................................. 12 1.2.1 Photoemission Electron Microscopy (PEEM) ................................................ 13 1.2.2 Low Energy Electron Microscopy (LEEM) .................................................... 17 1.2.3 Low Energy Electron Diffraction (LEED) ...................................................... 19 2.0 Experimental Methods ......................................................................................................... 21 2.1 UHV Components of LEEM/PEEM ........................................................................... 21 2.1.1 Cold Field Electron Emission Gun .................................................................. 21 2.1.2 Electron Optics .................................................................................................. 22 2.1.3 Projection Column ............................................................................................ 25 2.1.4 Apertures ........................................................................................................... 26 2.2 Sample Preparation ...................................................................................................... 27 2.2.1 Sample Stage ...................................................................................................... 27 2.2.2 Silicon Substrate Preparation .......................................................................... 28 2.2.3 Single Crystal Silver Pyramids and Wires ..................................................... 29 2.2.4 Single Crystal Silver Islands ............................................................................ 30 2.2.5 Polycrystal Silver Film ...................................................................................... 31 vii 2.2.6 Surface Structuring by Focused Ion Beam ..................................................... 32 2.3 Source of Photoemission .............................................................................................. 34 2.3.1 Mercury Lamp .................................................................................................. 34 2.3.2 Non-colinear Optical Parametric Amplifier (NOPA) .................................... 34 2.3.3 Interferometric Pump Probe setup.................................................................. 36 3.0 Simulation Framework ......................................................................................................... 38 3.1 Finite Difference Time Domain Algorithm ................................................................ 38 3.2 Reproduction of Static PEEM Images ........................................................................ 42 3.3 Reproduction of Time-Resolved PEEM ..................................................................... 45 3.4 Huygens Principle Algorithm ...................................................................................... 48 4.0 Propagating Surface Plasmon Polaritons (SPPs) ............................................................... 52 4.1 Propagating SPPs on Ag Wire ..................................................................................... 52 4.1.1 Co-propagation between Light and SPPs ....................................................... 52 4.1.2 Orthogonal Propagation between Light and SPPs .....