Dr. Pala was selected by the Army Research Laboratory (ARL) Multiscale Multidisciplinary Modeling of Electronic Materials (MSME) Collaborative Research Alliance (CRA) to participate as the Minority Serving Institution (MSI) partner. The award will provide support for several graduate students and computational infrastructure to perform 3D simulations of THz plasmonic structures.
Terahertz technologies utilize electromagnetic radiation in the frequency range between 300 GHz and 10 THz and their potential applications in biology, chemistry, medicine, astronomy and security are wide ranging. THz wavelengths have several properties that could promote their use as sensing and imaging tools. The envisioned prospect for THz applications fueled intense research in the last decade leading impressive advancements in emission and detection of THz radiation. Plasma wave propagation in various types of heterointerfaces has contributed to advancements in detection and control in THz spectral region. Because of the nature of plasma wave propagation, device response that surpasses the electronic drift cutoff frequency limit was possible. Resonant and non-resonant absorption of THz radiation by Si, III-V and GaN based semiconductor FET devices were observed. However, generation, propagation and absorption of THz radiation in novel materials and devices particularly nanostructures have yet to be studied. In the framework of the proposed research effort, we will analytically and numerically study the THz generation, propagation and absorption in new materials and structures to develop novel devices for defense-related applications.
For the simulation studies, we will employ FDTD technique using state of the art commercial software as well as home-developed code. Structures to be simulated can have a wide variety of electromagnetic material properties. The FDTD method is used to calculate how the EM fields propagate from the defined source through the structure to be investigated. Subsequent iterations provide information on field propagation in time. Typically, the simulation is run until there are essentially no electromagnetic fields left in the simulation region. Frequency domain information at any spatial point or group of points may be obtained through the Fourier transform of the time domain information at that point. The frequency dependence of power flow and modal profiles may be obtained over a wide range of frequencies from a single simulation. Recently, we performed 3D simulation of novel plasmonic concentrators to show that it is possible to focus THz radiation into deep sub-wavelength (down to l/150) field. In another recent study, we presented that room temperature THz resonant absorption with several higher order modes is possible in novel graphene-based FET-like structures.] We will take advantage of FIU’ s Panther Cluster high performance computing facility. This 380-CPU cluster allows us simulating complex structures in 3D with very high mesh density and hence with high resolution and accuracy. The materials and structures we plan to investigate include but not limited to graphene sheets and ribbons, graphene FETs and FET-like structures, nanowires of different semiconductors and heterostructures such as radial GaN/AIGaN, ZnO/ZnMgO, and GaAs/AIGaAs heterostructures, plasmonic crystals consisting of semiconductor grains in pyroelectric matrix and Si SoI micro-resonators.