Nanostructures based on semiconductors with special properties have been developed by Hebrew University of Jerusalem physicists with future applications for security cameras and spectrometers and medical imaging. Prof. Leonid Shvartsman and Prof. Boris Laikhtman of the university's Racah Institute of Physics have invented a novel design of TeraHertz-ray (T-ray) lasers. They said the novel device will have 400 times higher "gain" (a measure of power) than that of the only coherent T-ray sources existing today, called THz quantum cascade lasers. T-rays are electromagnetic waves with a wavelength shorter than microwave but longer than infrared. They could be very attractive for various imaging applications because they can penetrate substances ranging from clothing and walls; are harmless to humans and therefore can be used for healthcare and homeland security applications; and can detect various chemicals, especially explosives. Thus, T-ray-based devices can detect hidden weapons and explosives, as well as improve safety in healthcare by allowing an unlimited number of exposures for medical examinations, something not possible with x-rays. Despite all the advantages of T-rays, they are barely used due to a lack of T-ray emitters that can generate powerful, coherent and adjustable TeraHertz waves. The HU invention overcomes these limitations and portends the design of effective THz lasers, the scientists maintain. "TeraHertz rays are the imaging method of the future. They are comparable to x-rays in terms of their ability to penetrate opaque substances, but more importantly, they are harmless," said Yaacov Michlin, CEO of Yissum, the university's research development company, on Sunday. "The novel method to produce efficient T-ray emitters will enable the use of this important imaging source for various applications, including security and medical applications," he said.