Numerical Demonstration of THz Traveling Wave Amplifications in 2-D Electron Gas (2DEG) Under Scattering-Free and Low-Charge Density Regime

In this letter, we investigate the terahertz field fluctuations and dynamic interactions with electrons in a 2-D electron gas (2DEG) under the influence of slow wave structure in a substrate-based device. Low-charge density and the scattering-free regime are considered to maintain practical simulation times. The dynamics of this interaction are simulated using a co-planar waveguide (CPW)-connected interdigitated metal grating structure to provide electromagnetic (EM) excitation and phase velocity comparable to electron drift in the 2DEG channel. This letter demonstrates that interdigitated slow wave structure provides a media for synchronous interaction between electron gas and EM waves leading to amplification of charge density and velocity oscillations in a 2DEG. The method used for this numerical work is a full-wave-global numerical model that uses finite-difference time domain (FDTD)-based particle in cell solver of electron transport in 2DEG, with self-consistent EM field solution. Under the considered regime and device, the current oscillations show an increase in amplitude which illustrates the effect of synchronous interaction between the 2DEG.