Terahertz frequencies consist of electromagnetic waves (T-rays or T-light) in the region of the electromagnetic spectrum between 300 gigahertz and 3 terahertz, at the ending edge of far-infrared light.

These waves usually travel in the line of sight, are non-ionizing and have the capability to penetrate a wide variety of non-conducting materials, like clothing, paper, cardboard, wood, masonry, plastic and ceramics, even clouds and fog, but, until now, it couldn't penetrate metal or water.

Now, researchers directing this special type of light at metal poked with holes in irregular patterns, recently discovered that all the light behaved like a liquid and fell across the metal to find its way through the escape holes.

Light, in this case, was acting extremely weird, since, for example, if you shine a flashlight at a colander, some of this light will travel through holes, but you would expect the solid part of the colander to keep much of the light from shining through.
The strange thing is that in this experiment, the light traveled around the thin sheet of metal through patterned holes and all of it came out the other side. "You can get 100 percent transmission of light, even if holes only make up 20 percent of the area," University of Utah physicist Ajay Nahata, of the scientists who performed the experiment.

"It was surprising, because a hole is the simplest thing you could imagine," said electrical engineer Daniel Mittleman, who works in Rice University's T-ray lab.

The explanation is not so obvious as the results: "By using terahertz, you can really see how and when light comes out of the holes. Once you illuminate the hole, some light goes through and some comes out a little later", said Mittleman.

Can we assume that the behavior they observe of the terahertz radiation, since all light waves tend to act similarly, also occurs across the electromagnetic spectrum?

That is what that will be trying to prove at later stages of the experiment.

This could pave the way for a number of important applications of terahertz radiation in wireless communication and security operations, and since many everyday materials, such as clothing, plastics and wood look transparent under terahertz imaging, the technology could be used to spot concealed bombs and other explosive devices.

In addition, materials absorb T-rays at varying frequencies, depending on the type of material. Anthrax, for example, can be detected with terahertz imaging by its frequency fingerprint.