Multiphysics Simulation of Plasmonic Photoconductive Devices using Discontinuous Galerkin Methods

TL;DR

This paper introduces a novel multiphysics simulation framework using discontinuous Galerkin methods to model complex plasmonic photoconductive devices, capturing electromagnetic and carrier interactions in stationary and transient states.

Contribution

It develops a new DG-based multiphysics simulation framework specifically designed for intricate plasmonic PCDs, addressing challenges of multiscale and nonlinear interactions.

Findings

Accurately simulates stationary and transient plasmonic PCDs

Handles multiscale space and time characteristic differences

Demonstrates applicability through simulation results

Abstract

Plasmonic nanostructures significantly improve the performance of photoconductive devices (PCDs) in generating terahertz radiation. However, they are geometrically intricate and result in complicated electromagnetic (EM) field and carrier interactions under a bias voltage and upon excitation by an optical EM wave. These lead to new challenges in simulations of plasmonic PCDs, which cannot be addressed by existing numerical frameworks. In this work, a multiphysics framework making use of discontinuous Galerkin (DG) methods is developed to address these challenges. The operation of the PCD is analyzed in stationary and transient states, which are described by coupled systems of the Poisson and stationary drift-diffusion (DD) equations and the time-dependent Maxwell and DD equations, respectively. Both systems are discretized using DG schemes. The nonlinearity of the stationary system is accounted for using the Gummel iterative method while the nonlinear coupling between the time-dependent Maxwell and DD equations is tackled during time integration. The DG-based discretization and the explicit time marching help in handling space and time characteristic scales that are associated with different physical processes and differ by several orders of magnitude. The accuracy and applicability of the resulting multiphysics framework are demonstrated via simulations of conventional and plasmonic PCDs.