Design of Photoconductive Antenna for THz Wave Generation

Abstract

Recently, a novel solution to the generation and detection of terahertz electromagnetic waves, the photoconductive antenna (PCA), has been intensively studied. However, the problem of this kind of antenna is the low output power and low optical-to-terahertz energy conversion efficiency. A novel plasmonic structure antenna is studied with the intention of improving the conversion efficiency (C. W. Berry et al., 2011). This report presents simulations for both conventional PCAs and plasmonic enhanced PCAs using the built-in Semiconductor module and the Radio Frequency (RF) module in COMSOL Multiphysics®. Unlike traditional antennas, PCAs are excited by femtosecond laser illumination. Characteristics like electric field distribution, optical absorption and photocurrent were simulated and analyzed in time-domain and frequency-domain. The results indicated a possible 5.2 times photocurrent enhancement with the implementation of plasmonic structure. This work provides a method to predict the performance of future structures before the complex fabrication and testing processes.