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Tuesday, February 20, 2007 T-Rays Advance Toward Airport ScreeningContinued from page 1 By Neil Savage
Hu's lasers are a "key component" of a terahertz security device that Sandia National Laboratory is developing, says Sandia principal investigator Mike Wanke. The three-year project at the lab, now in its second year, aims to integrate a laser source and a detector into the same device. That eliminates complex optical setups and improves detector sensitivity by orders of magnitude, Wanke says. He envisions a module that can be used to make compact, commercially viable t-ray systems for use in airports. "We're trying to make this so it's a turnkey, drop-into-place system," he says. He adds that once Sandia has a successful prototype, businesses can tackle the challenge of product development. The lasers need to reach lower frequencies to do a better job of penetrating material--the lower, the better, says Hu. But lower frequencies mean smaller quantum wells, which are harder to build accurately. Hu won't predict when commercial systems could be available. But Xi-Cheng Zhang, director of Rensselaer Polytechnic Institute's Center for Terahertz Research says Hu "always breaks the record he sets for himself." Zhang says that either improvements in the engineering or use of different semiconductor materials is likely to make even better quantum cascade lasers. He expects that most of the problems will be solved in a year or two. One such problem is that the lasers operate at cryogenic temperatures and require bulky cooling equipment; Hu holds the record for highest operating temperature. After such problems are solved, market forces rather than technical issues will determine how long it takes for a commercial scanner to show up in an airport, Zhang says. Hu says that the technology is of particular interest to, besides commercial air-travel applications, the military. "DARPA [the Defense Advanced Research Projects Agency] is very interested in this to identify suicide bombers," he says. T-rays aren't the only way to do this; other systems reaching market use radar and vision-processing software. (See "Walking like a Bomber.")Zhang founded a company, Zomega Terahertz that makes a laptop-size T-ray detector that can be attached to a flying drone for remote detection of chemical and biological substances. While the trillionths of a watt produced by the infrared laser in the device is fine for spectroscopic analysis of air samples, it's not adequate for imaging, and the laser technology is unlikely to improve enough to be used in airport security, Zhang says. He believes that quantum cascade lasers are the future of T-ray detection systems: "They will be the final winner in the market." |
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A Compact Chemical Sensor
04/30/2008
Comments
nekote on 02/20/2007 at 7:38 AM
115
How about trying these scanners out in (men's) prisons first, where such issues would be a lesser degree of concern, than necessary security?
Failure to detect "shanks" (home made stabbing / cutting weapons) truly have murderous results.
Detecting contraband would also be extremely valuable.
mkogrady on 02/20/2007 at 7:02 PM
92
One "whole body" scanner - external model
One "inner body" scanner - with replacement doo-hicky's (emphasis on Doo!)
blunney on 02/20/2007 at 9:19 AM
15
The TSA is watching you...
jsessex on 02/20/2007 at 1:18 PM
12
cyberpageman on 02/21/2007 at 12:46 PM
24
When x-rays were first discovered, there was worry about them too. I remember my physics professor quoting:
The Roentgen Rays, the Roentgen Rays,
What is this craze?
The town's ablaze
With the new phase
of X-Ray's ways.
I'm full of daze,
shock and amaze;
For nowadays
I hear they'll gaze
Thro' cloak and gown--and even stays,
Those naughty, naughty Roentgen Rays
No one worries about Superman's x-ray vision, so why worry about terahertz rays, which are a lot less clear?
abcarterjr on 02/21/2007 at 12:30 PM
45
classify a mountain stream as a go-nogo carrier
of micron gold?
ggeek99 on 02/24/2007 at 2:01 AM
2
Why should it be illegal for adults to eat/smoke/drink the compounds of their choosing in a free society? How can society/government maintain a list of approved and nonapproved foods & drugs for adult members of that society?
Why can I not carry a weapon for my protection in a society where the police are armed to the gills and trigger happy and the crooks likewise?
There is no place where people respect each other more than the parking lot of a gunshop. No one cuts each other off, no one takes anothers parking space. Why? Because they know the other maybe packing heat. Perhaps we would all respect each other a little bit more if we knew we could all defend ourselves in the heat of argument, so why argue?
If army exists to keep the peace, then so must guns. So why the hurry to disarm the civilian populace and arm the police & military?
If we implement perfect screening technologies without understanding the implications for our political futures then we deserve the future we get, not matter how how fascist or tyrannical.