backtop


Print 18 comment(s) - last by xdfxdf.. on Dec 23 at 2:47 PM


Future scanners will tell the difference between Advil and meth  (Source: MIT)
New scanner tech uses terahertz lasers

Airport security is a huge objective in the United States these days. Airports in America and around the world are beefing up security and researchers scattered around the globe are working hard at developing scanners and detectors that are better at finding potential weapons and explosives that people may try to get onboard aircraft.

New scanner technology that was shown off first in May of 2009 dubbed "whole-body imaging" scanners had passengers and privacy advocates up in arms over the fact that the scanners were able to see through clothing and show anatomical details of passengers. The scanners are deployed at 40 airports at a cost of about $170,000 each. The scanners blur the face of the person being scanned and only the scanner operator sees the scans.

Researchers at MIT have developed a new technology that may one day allow scanners in airports to tell if the substance inside a medication vial is an illegal drug or an explosive. The technology uses lasers with a frequency in the terahertz spectrum. Lasers operating in the terahertz range are absorbed by different molecules in different amounts allowing scanners using the lasers to tell the difference between chemicals.

The researchers say that accurately determining the chemical composition of objects requires exposing it to different and continuous ranges of terahertz frequencies. MIT professor Qing Hu and colleagues have published a paper in the latest issue of Nature Photonics that outlines a method for tuning terahertz quantum cascade lasers. This is the most promising type of laser to provide the needed terahertz radiation for scanners. Terahertz radiation is also said to be safer for human exposure than x-ray radiation.

Researchers discovered that terahertz lasers could be tuned by bringing a block of another material close to the laser beam. The blocks change the wavelength of the laser light allowing for different frequencies. A metal block was found to shorten the wavelength of the laser and a silicon block lengthened it. Varying the distance of the blocks to the laser also changed the extent of the frequency shift in the laser.

The researchers have designed and are now building chips that use microelectromechanical devices to bring the silicon and metal blocks close to the laser from different directions to vary the wavelengths from short to long. In experiments, the researchers used a mechanical arm to move the blocks.



Comments     Threshold


This article is over a month old, voting and posting comments is disabled

By Anoxanmore on 12/8/2009 12:51:32 PM , Rating: 2
Ahh, so that explains all those orange suits I saw while I was visiting MIT.


"I f***ing cannot play Halo 2 multiplayer. I cannot do it." -- Bungie Technical Lead Chris Butcher














botimage
Copyright 2014 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki