Photoconductive antennas deposited onto GaAs substrates that incorporate InAs quantum dots have been recently shown to efficiently generate both pulsed and CW terahertz radiation. In this Letter, we determine the operational limits of these antennas and demonstrate their extreme thermal breakdown tolerance. Implanted quantum dots serve as free carrier capture sites, thus acting as lifetime shorteners, similar to defects in low-temperature grown substrates. However, unlike the latter, defect-free quantum-dot structures possess perfect lattice quality, thus not compromising high carrier mobility and pump intensity stealth. Single gap design quantum dot based photoconductive antennas are shown to operate under up to 1W of average pump power (1:6mJ cm -2 energy density), which is more than 20 times higher than thepumping limit of low-temperature grown GaAs based substrates. Conversion efficiency of the quantum dot based hotoconductive antennas does not saturate up to 0.75W of pump power (1:1mJ cm -2 energy density). Such a thermal tolerance suggests a glowy prospect for the proposed antennas as a perspective candidate for intracavity optical-to-terahertz converters.
Bibliographical noteFunding Information:
This project has received funding from Engineering and Physical Sciences Research Council (EPSRC), Grant No. EP/ R024898/1. A.G. thanks Magicplot Ltd. for providing a copy of MagicPlot Pro plotting and fitting software used for preparation of the figures in this manuscript.
© 2021 Author(s).