Optically driven photoconductive switches are one of the predominant sources currently used in terahertz imaging systems. However, owing to their low average powers, only raster-based images can be taken, resulting in slow acquisition. In this work, we show that by placing a photoconductive switch within a cavity, we are able to generate absolute average THz powers of 181 μW with the frequency of the THz emission centered at 1.5 THz—specifications ideally adapted to applications such as non-destructive imaging. The cavity is based on a metal–insulator–metal structure that permits an enhancement of the average power by almost 1 order of magnitude compared to a standard structure, while conserving a broadband spectral response. We demonstrate proof-of-principle real-time imaging using this source, with the broadband spectrum permitting to eliminate strong diffraction artifacts.

中文翻译：

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用于实时太赫兹成像的腔基光电导源

光驱动光电导开关是目前太赫兹成像系统中使用的主要光源之一。然而，由于它们的平均功率低，只能拍摄基于光栅的图像，导致采集速度缓慢。在这项工作中，我们表明通过在腔内放置光电导开关，我们能够产生 181 μW 的绝对平均太赫兹功率，太赫兹发射的频率以 1.5 太赫兹为中心——这些规格非常适合非破坏性应用等应用成像。腔体基于金属-绝缘体-金属结构，与标准结构相比，平均功率提高了近 1 个数量级，同时保持了宽带光谱响应。我们使用此源演示了原理验证实时成像，