"T-waves" are all over the news lately, it seems like they can perform all types of sensor magic. In September 2016, MIT and Georgia Tech announced that they read nine pages of a closed book using T-waves. Once this technology is developed it will be used to image antique books without risk of damaging them; many artifacts are so fragile they can't survive the act of opening them.
There are various definitions for what frequencies constitute "terahertz". Although "tera" implies 10^12, the casual definition of T-waves encompasses 300 GHz to 3 THz. Above 3 THz is considered the far edge of infrared spectrum.
One system application that has been fielded is for screening passengers at airports by seeing through clothing. It is possible to create an entirely passive sensor at terahertz frequency. However, passive (radiometric) sensors take much longer time to construct an image, and we don't want to wait any longer in security lines, do we?
Recent articles have provided evidence that exposure to T-waves can "unzip" DNA molecules. We'll wait for more research on this before we offer our opinion(s).
Below is a video from Texas Instruments on fundamentals of terahertz waves, from their "white board" series on innovation.
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