The research team led by Kodo Kawase of Nagoya University developed a technology to detect narcotic and stimulant drugs in an envelope without opening it. The technology narrows down the components of what is contained in an envelope using terahertz waves. It is effective to detect these illegal drugs inside an international mail envelope made from heavy paper. Although terahertz waves go through paper, terahertz waves of a specific wavelength are absorbed when they hit narcotic and stimulant drugs. Because legal drugs and foods contain more impurities than narcotic drugs, they absorb terahertz waves of a wide range of wavelength. The research team members utilized this characteristic to detect narcotic and stimulant drugs.
They built a 50 cm square trial model and successfully distinguished 20 kinds of narcotic and stimulant drugs contained in envelope from legal drugs and foods contained in envelope. This technology can be used for antiterrorism measures because it is effective not only to detect illegal drugs but also to detect explosives. They plan to make the technology practicable in a few years with a view to using it in airports and international post offices. At the present stage, it costs about 30 million yen to build equipment based on this technology, but they wish to reduce the cost to one tenth.
Now it is possible to detect illegal drugs in
an envelope without opening it.