title: Excitation-density-dependent generation of broadband terahertz radiation in an asymmetrically excited photoconductive antenna.
abstract: The generation of terahertz (THz) transients in photoconductive emitters has been studied by varying the spatial extent and density of the optically excited photocarriers in asymmetrically excited, biased low-temperature-grown GaAs antenna structures. We find a pronounced dependence of the THz pulse intensity and broadband (>6.0 THz) spectral distribution on the pump excitation density and simulate this with a three-dimensional carrier dynamics model. We attribute the observed variation in THz emission to changes in the strength of the screening field.
authors: School of Electronic and Electrical Engineering, University of Leeds, Leeds, UK. p.upadhya@leeds.ac.uk
authors: Prashanth C
authors: PC
authors: Upadhya
authors: Wenhui
authors: W
authors: Fan
authors: Andrew
authors: A
authors: Burnett
authors: John
authors: J
authors: Cunningham
authors: A Giles
authors: AG
authors: Davies
authors: Edmund H
authors: EH
authors: Linfield
authors: James
authors: J
authors: Lloyd-Hughes
authors: Enrique
authors: E
authors: Castro-Camus
authors: Michael B
authors: MB
authors: Johnston
authors: Harvey
authors: H
authors: Beere