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It seems like every time I set foot in an airport, there is some new machine I need to stand in, walk through, or put my shoes on. The argument can be made that much of this is security theater — an effort to just make things look safe. However, if a new kind of laser-based molecular scanner lives up to its promise and finds its way into airports as planned, it could actually make a difference. Some are calling foul on the possible privacy concerns, but this technology is halfway to a Star Trek tricorder.
A company called Genia Photonics has developed a programmable picosecond laser that is capable of spotting trace amounts of a variety of substances. Genia claims that the system can detect explosives, chemical agents, and hazardous biological substances at up to 50 meters. This is why the US Department of Homeland Security is so keen on getting it into airports.
Much is being made about the “laser” aspect of this device, but if you’re picturing a coherent beam of light sweeping over you in the security line, think again. This device relies on classic spectroscopy; just a very advanced form of it. A spectrometer is simply a device that uses radiated energy to characterize a material. In the case of Genia’s scanner, it is using far-infrared radiation in the terahertz band.
Terahertz radiation is at the extreme high end of infrared; almost microwave, in fact. The wavelengths used in this technology are much longer than that of visible light — about 100,000-1,000,000 nanometers versus just 790 nanometers for visible red light. If you step down in the infrared wavelengths, closer to visible light, you find the spectrum used for infrared cameras. That should tell you why the terahertz spectrum is so good for scanning; infrared cameras can see through some obstacles. The effect is even more pronounced with the lower wavelength terahertz radiation.
The beam used by Genia’s spectrometer is capable of penetrating most materials including wood, leather, cloth, ceramics, plastic, and paper. Worryingly, that means it can essentially scan the surface of your body through clothing looking for traces of dangerous substances. The terahertz signals used are non-ionizing and very low power, so at least it’s safe.
It’s important to understand that this is not an imaging device, but a tool for reading absorbance spectra. Some of the radiation emitted will be absorbed by everything (and everyone) it is directed at. Because different compounds absorb that energy in different ways, the profile of energy returned to the scanner can tell you what it “saw.”
I am simultaneously fascinated by the potential of this technology, and disturbed by the amount of data it would be able to gather on hapless travelers. This kind of picosecond laser reads the environment in real-time. That gunpowder residue on your hand from hunting the other day, cannabis smoke particles in your hair, or even a bit of (explosive-boosting) nitrate fertilizer stuck to your shoe could trigger this scanner. Will that cause an entirely new set of headaches for airline passengers?
There are still reasons to be skeptical about Genia’s claims. A 50 meter range is amazing, for instance. Most spectroscopy is done at very close range to avoid interference. If this does work as advertised, it’s going to do some of the things a tricorder from Star Trek would. Imagine a device you can point at something to find out instantly what it’s made of. Or perhaps a medical scanner that can read the telltale cellular markers for cancer and other diseases. Genia specifically cites these kinds of applications.
It is genuinely concerning that this device could be abused to invade your privacy, but used correctly it might be less troublesome than a pat down at the airport. It will all come down to how it’s implemented.
Read more at Gizmodo
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