Surface Plasmon Polaritons at Terahertz Frequencies on Metal and Semiconductor Surfaces

Inhaltsverzeichnis (Table of Contents)

• Introduction
  • Electromagnetic interface excitations
  • Surface plasmon polariton
  • Terahertz frequency range
  • Conceptual formulation of this thesis
• Theory of Surface Plasmon Polaritons
  • Classical field equations
  • Surface plasmon polaritons at a single interface system
  • Surface plasmon polaritons at a two interface system
  • The Drude model
    • A classical model for metals
    • Modified Drude model for doped semiconductors.
    • Optical properties of investigated materials
    • Limitations of the Drude model
  • Numerical results for single and two interface systems
    • SPPs at gold and semiconductor surfaces
    • SPPs at dielectric covered gold surfaces
  • Coupling between free electromagnetic waves and surface plasmon polaritons
    • Aperture coupling
    • Prism coupling
    • Grating coupling
• Experimental Setup
  • Terahertz time-domain SPP spectroscopy
  • Sample fabrication
• Experimental Results
  • Coupling of Free Electromagnetic Radiation to Surface Plasmon Polaritons.
    • Aperture coupling
    • Prism coupling
  • Study of dielectric coated gold surfaces
  • Study of semiconductor surfaces
    • SPP decay perpendicular to the semiconductor surface into air
    • SPP damping along the propagation direction

Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)

This thesis investigates the properties of surface plasmon polaritons (SPPs) at terahertz frequencies on metal and semiconductor surfaces. The research explores the generation, propagation, and interaction of SPPs with different materials and structures.

• Surface plasmon polariton excitation and propagation at terahertz frequencies
• Experimental characterization of SPPs using terahertz time-domain spectroscopy
• Influence of different materials and surface structures on SPP properties
• Potential applications of SPPs in terahertz technology

Zusammenfassung der Kapitel (Chapter Summaries)

The thesis begins with an introduction to the concept of electromagnetic interface excitations and surface plasmon polaritons (SPPs), focusing on the terahertz frequency range. The theoretical framework of SPPs is then developed, exploring classical field equations, SPP behavior at single and two-interface systems, and the Drude model for describing metallic and semiconductor materials. The chapter also presents numerical results for SPP characteristics on gold and semiconductor surfaces.

The thesis delves into various methods for coupling free electromagnetic waves to SPPs, including aperture, prism, and grating coupling techniques. The experimental setup, including terahertz time-domain SPP spectroscopy and sample fabrication methods, is described in detail. Experimental results are presented for different coupling methods and surface configurations, including dielectric-coated gold surfaces and semiconductor surfaces. The thesis concludes by examining the decay and damping behavior of SPPs on semiconductor surfaces.

Schlüsselwörter (Keywords)

The main keywords of this thesis include surface plasmon polaritons, terahertz frequencies, time-domain spectroscopy, gold, semiconductors, surface structure, coupling techniques, propagation, and damping.