Visions 22: T-rays

Exploiting a neglected part of the electromagnetic spectrum

Visions 22 – T-rays

We rely on electromagnetic radiation – from the shortest-wavelength gammarays and X-rays, through visible light, to longer-wave microwaves and radio waves – to observe and manipulate the world around us. 

Physicists and engineers have developed a wide range of sources, sensors and techniques that operate across the electromagnetic spectrum and are used in communications, imaging and analysis. 

However, one part of the spectrum, has stayed in the dark. Terahertz radiation, which lies between the infrared and microwave regions, covering frequencies between 300 gigahertz and 3 terahertz (3 million million cycles a second), has been little used (see spectrum above). 

This was because there were no practical sources or detectors of terahertz radiation – traditional optical and electronic devices work above and below this region and depend on different technologies.

Visions 22: T-rays (PDF, 134 KB)