In recent years, the characterization of radiation falling within the so-called “terahertz (THz) gap” has become an ever more prominent issue due to the increasing use of THz systems in applications such as nondestructive testing, security screening, telecommunications, and medical diagnostics. THz detection technologies have advanced rapidly, yet traceable calibration of THz radiation remains challenging. In this paper, we demonstrate a system of electrometry in which a THz signal can be characterized using laser spectroscopy of highly excited (Rydberg) atomic states. We report on proof-of-principle measurements that reveal a minimum detectable THz electric field amplitude of $1.07 \pm 0.06\; {\rm{V}}/{\rm{m}}$ at 1.06 THz (3 ms detection), corresponding to a THz power at the atomic cell of approximately 3.4 nW. Due to the relative simplicity and cryogen-free nature of this system, it has the potential to provide a route to a SI traceable “atomic candle” for THz calibration across the THz frequency range, and provide an alternative to calorimetric methods.

中文翻译：

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通过原子蒸气的红外光谱进行太赫兹电测量

近年来，由于太赫兹系统在无损检测、安检、电信和医疗等应用中的使用越来越多，在所谓的“太赫兹 (THz) 间隙”内的辐射表征已成为一个越来越突出的问题。诊断。太赫兹探测技术发展迅速，但太赫兹辐射的可溯源校准仍然具有挑战性。在本文中，我们展示了一种电测量系统，其中可以使用高激发（里德伯）原子态的激光光谱来表征太赫兹信号。我们报告了原理验证测量结果，该测量结果显示最小可检测太赫兹电场幅度为$1.07 \pm 0.06\；{\rm{V}}/{\rm{m}}$在 1.06 THz（3 ms 检测）下，对应于原子电池的 THz 功率约为 3.4 nW。由于该系统的相对简单性和无冷冻剂特性，它有可能为在太赫兹频率范围内进行太赫兹校准提供通往 SI 可溯源“原子蜡烛”的途径，并提供量热方法的替代方案。