Terahertz Waveguide Spectroscopy of Two - Dimensional Plasmons in GaAs

The electrical characteristics of high-mobility, two-dimensional electron gas (2DEG) systems, such as GaAs quantum wells, have been well-studied at low frequencies and in extreme conditions of high magnetic fields and ultralow temperatures. While highfrequency excitations of 2DEGs have been examined to some extent from microwave to terahertz (THz) frequencies, a fundamental understanding of the physical properties of 2DEGs in this range have by no means been mastered. To address this matter, this thesis focused on studying a fundamental, high-frequency collective excitation, known as the plasmon, to better understand plasmon damping and coupling mechanisms in GaAs quantum well 2DEGs. The experiments utilized THz waveguide spectroscopy to study the low-temperature behavior of 2D plasmons. Thesis Supervisor: Rajeev J. Ram Title: Professor of Electrical Engineering