Researchers at the Massachusetts Institute of Technology (MIT) and the University of Waterloo have developed a high-power, portable quantum cascade laser that can generate terahertz radiation outside the laboratory environment. This laser may be used in areas such as precise location of skin cancer and detection of hidden explosives.
These lasers are only a few millimeters long and are quantum well structures with carefully customized wells and barriers. In this structure, the electrons “cascade” down a kind of ladder, each step of which emits a light particle, that is, a photon. An important innovation in the research is to double the height of the barrier inside the laser to prevent the leakage of electrons, which tends to increase at high temperatures.
In the medical field, this new portable system includes a compact camera and detector, which can be operated in any place with a power outlet, and can provide real-time imaging during skin cancer screening and even during surgery to remove skin cancer tissue. Professor Hu said that cancer cells “behave very clearly in terahertz” because their water and blood concentrations are higher than normal cells. The technology can also be applied to many industries that need to detect foreign objects inside products to ensure product safety and quality.
