New promise for terahertz wave imaging

Much of the electromagnetic spectrum has provided science and medicine with ways of looking inside matter. Terahertz waves, lasting a millionth of a millionth of a second and sitting between microwaves and infrared on the EM spectrum, are one the most recent additions to the imaging armoury, and have very attractive properties particularly for medicine.

With much less energy than x-rays, they do not damage DNA or living tissue; moreover, they interact in specific ways with matter making them a useful tool for spectroscopy to characterise materials. They can also pass through nonconductive materials, which could make them useful for security screening.

However, terahertz waves have until now been difficult to use, because they require complex, bulky and expensive equipment to both generate and analyse. Researchers at Princeton University in New Jersey, US, have now developed a pair of compact microchips that can generate and receive terahertz waves that could, they claim, revolutionise their use, moving away from devices with arrays of mirrors, lenses and lasers and towards compact desktop or even handheld systems.