Besides having to remove our shoes, the volume limitations regarding liquids and gels in carry-on baggage has become a major hassle in the world of post 9-11 airport security. Hopefully, however, we may soon be able to once again bring our big bottles of water and tubes of toothpaste aboard airliners in our overnight bags. Britain's Cobalt Light Systems has developed a scanner called the INSIGHT100, that uses laser light to assess the liquid contents of containers, even if those containers are opaque.
The scanner utilizes Spatially Offset Raman Spectroscopy, or SORS. The process begins with security personnel placing an individual container inside the microwave oven-sized device. Then, the system shines a near-infrared laser into that container at various locations. Some of that light is reflected back to the device by the liquid. The wavelength of that light, however, is shifted by energy levels of the liquid's molecules. By assessing the wavelength shifts of those various light readings, the machine is able to identify what the liquid is - within five seconds, to boot.