Contribution assessment of antenna structure and in-gap photocurrent in terahertz radiation of photoconductive antenna
AffiliationUniv Arizona, Dept Elect & Comp Engn
MetadataShow full item record
PublisherAMER INST PHYSICS
CitationJournal of Applied Physics 124, 053107 (2018); doi: 10.1063/1.5038341
JournalJOURNAL OF APPLIED PHYSICS
Rights© 2018 Author(s). Published by AIP Publishing.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at firstname.lastname@example.org.
AbstractPhotoconductive antenna (PCA) is one of the most widely used terahertz (THz) devices nowadays. Although PCAs have been extensively studied through both theoretical analysis and device design, there still lacks a common agreement upon the mechanism of THz radiation. One of the central questions is how to distinguish and assess the contribution of the antenna structure and in-gap photocurrent to the overall radiation of a PCA. In this work, a three-dimensional full-wave model was first used to quantify the overall far-field radiation of PCAs. The commercial solver (i.e., HFSS) and the Hertzian dipole approximation method were then applied to quantify the far-field radiation solely from the antenna structure and in-gap photocurrent, respectively. The contribution of the antenna structure and in-gap photocurrent can therefore be distinguished by comparing the simulation results among the three methods. The results suggest that, although the THz radiation originates from laser-excited photocurrent within the gap, the overall THz radiation of a PCA is predominated by the antenna structure. As a validation, the cancellation effect was predicated by numerical simulation of coplanar stripline PCA and confirmed with experiment using butterfly shaped stripline PCA. The presented work uncovers the details of the underlying radiation mechanism of the PCA. This could inspire PCA design that aims for engineering the radiation properties of a PCA for specific applications. Published by AIP Publishing.
Note12 month embargo; published online: 7 August 2018
VersionFinal published version
SponsorsNational Science Foundation Major Research Instrument Program