The World’s Most Powerful Terahertz Quantum Cascade Laser

Whether it is diagnostic imaging, analysis of unknown substances or ultrafast communication - terahertz radiation sources are becoming more and more important. At the Vienna University of Technology, an important breakthrough has been achieved. Terahertz waves are invisible, but incredibly useful; they can penetrate many materials which are opaque to visible light and they are perfect for detecting a variety of molecules. Terahertz radiation can be produced using tiny quantum cascade lasers, only a few millimetres wide. This special kind of lasers consists of tailor made semiconductor layers on a nanometer scale. At the Vienna University of Technology (TU Vienna) a new world record has now been set; using a special merging technique, two symmetrical laser structures have been joined together, resulting in a quadruple intensity of laser light. Jumping Electrons Create Terahertz Light - For the electrons in each layer of the quantum cascade laser, only certain discrete energy levels are allowed.