Global Modeling of Active Terahertz Plasmonic Devices

In this study, a full wave numerical technique is employed to characterize the propagation properties of 2-D plasmons along two-dimensional electron gas (2DEG) layers of biased hetero-structures at terahertz frequencies. This method is based on a coupled solution of Maxwell and hydrodynamic transport equations. In this manner, a complete description of carrier-wave interactions inside the 2DEG layer is obtained. Particularly, this simulator is employed to investigate the 2-D plasmon variations initiated by the application of an external bias along the hetero-structure. Substantial changes in the plasmon characteristics such as wavelength and decay length are reported. It is also revealed that two symmetrical plasmonic modes along the unbiased 2DEG layer split into new asymmetrical ones after applying the bias voltage. The simulation has been performed in different structures to examine the effects of various electron densities and the presence of periodic metallic gratings on the plasmon properties. Moreover, the 2-D plasmon reflections from boundaries terminated by ohmic contacts are separately studied. This research demonstrates the potentials of the 2-D conductors in the design of novel active terahertz plasmonic devices as modulators and amplifiers while proposing a new approach for their modeling. The results of this simulation are verified independently with an analytical model.