Non-destructive testing of materials by time-domain terahertz (THz) imaging

太赫兹（THz）波覆盖了从100 GHz到15太赫兹的电磁区域，从而弥合了微波和红外线（IR）光之间的差距。长期以来，由于缺乏太赫兹源，即所谓的“太赫兹频率间隙”，这个频率范围一直未被探索。今天太赫兹光的亮度为从光谱成像到超高速短距离电信设备的新应用打开了大门。然而，为了直接影响工业，简单的生成和检测方案仍有待发现，这将使交钥匙应用成为可能（例如，在太赫兹频率下进行高效、非破坏性的评估）。预期的方法是结合不同的技术，如电子和等离子体，以实现新的太赫兹系统，以比实际系统更低的成本提供数量级的性能改进。这将使太赫兹辐射能够用于获得使用x射线或红外辐射无法获得的重要物理数据。

Terahertz (THz) waves cover the electromagnetic region from 100 GHz to 15 THz, thus bridging the gap between microwaves and infrared (IR) light. For long time, this frequency range has been unexplored due to a lack of THz source, the so-called ‘THz frequency gap’. Today’s brightness of THz light opens up the door for novel applications ranging from spectroscopic imaging to ultra-high speed short-range telecommunication devices. To directly impact the industry, however, simple generation and detection schemes are still awaiting to be discovering that will enable turnkey applications (e.g. for efficient, non-destructive evaluations at THz frequency). The anticipate approach is to combine different technologies, such as electronics and plasmonics, for realizing novel THz systems that offer orders of magnitude improvements in performance at lower cost than actual systems. This will enable THz radiation to be used to obtain important physical data that are not accessible using X-ray or infrared radiation.