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 1 W of average pump power ($\sim 1.6\hspace{0.17em}\text{mJ}\hspace{0.17em}{\text{cm}}^{-2}$ energy density), which is more than 20 times higher than the pumping limit of low-temperature grown GaAs based substrates. Conversion efficiency of the quantum dot based photoconductive antennas does not saturate up to 0.75 W of pump power ($\sim 1.1\hspace{0.17em}\text{mJ}\hspace{0.17em}{\text{cm}}^{-2}$ energy density). Such a thermal tolerance suggests a glowy prospect for the proposed antennas as a perspective candidate for intracavity optical-to-terahertz converters.

中文翻译：

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基于量子点的太赫兹光电导天线在极端泵浦条件下的运行

沉积在包含 InAs 量子点的 GaAs 衬底上的光电导天线最近已被证明可以有效地产生脉冲和 CW 太赫兹辐射。在这封信中，我们确定了这些天线的操作限制并展示了它们的极端热击穿耐受性。注入的量子点用作自由载流子捕获位点，从而起到缩短寿命的作用，类似于低温生长基板中的缺陷。然而，与后者不同的是，无缺陷的量子点结构具有完美的晶格质量，因此不会影响高载流子迁移率和泵浦强度隐身性。单间隙设计基于量子点的光电导天线可在高达 1 W 的平均泵浦功率下运行（$～1.6\hspace{0.17em}\text{兆焦耳}\hspace{0.17em}{\text{厘米}}^{-2}$能量密度），比低温生长的 GaAs 基衬底的泵浦极限高 20 倍以上。基于量子点的光电导天线的转换效率不会饱和高达 0.75 W 的泵浦功率（$～1.1\hspace{0.17em}\text{兆焦耳}\hspace{0.17em}{\text{厘米}}^{-2}$能量密度）。这种热耐受性表明所提出的天线作为腔内光到太赫兹转换器的潜在候选者具有广阔的前景。