From your friends at Gizmodo (http://gizmodo.com/5923980/the-secret-government-laser-that-instantly-knows-everything-about-you):
Within the next year or two, the U.S. Department of Homeland Security will instantly know everything about your body, clothes, and luggage with a new laser-based molecular scanner fired from 164 feet (50 meters) away. From traces of drugs or gun powder on your clothes to what you had for breakfast to the adrenaline level in your body—agents will be able to get any information they want without even touching you.
And without you knowing it.
Great scare headline and really neat gadget to use in a story. I scanned over the web site for the Genia Photonics company (http://www.geniaphotonics.com/business-markets/defense-and-security/terahertz-spectroscopy/) and, as expected, they aren’t quite as out of breath when describing their work as Gizmodo is.
There are some scary invasion of privacy issues here. I don’t have the link, but I recall reading articles about issuing police THz radar scanners with which they could assess whether or not passersby were armed and then react accordingly. The article that I’m claiming to have read indicated that this capability would be considered an unlawful search and therefore the police could not be provided with it.
Not knowing how their devices work, I suspect that there are quite a few interesting technical challenges to be overcome before it can be used in a practical way. Examples are calibration standards for the frequencies they are searching for (as molecular indicators)–are these hard to do or easy?
A few seconds spent worshipping at Google’s altar provided these links:
http://www.tstnetwork.org/December2010/tst-v3n4-192Recent.pdf Chinese researchers reported work using THz detection mechanisms. In their summary they say:
THz spectroscopy serves as useful technique in identifying biological molecules and medicine, studying molecular structure and discerning some diseased tissues. Despite of that, a great many problems remain to be challenging.
They didn’t really elaborate on the difficulties.
This older (2006) article indicates the problem is the hardware used to generate the THz signals and to detect them–cryogenic cooling, other challenges depending upon the technique. (http://spie.org/x13756.xml)
This abstract (http://orbit.dtu.dk/en/publications/terahertz-spectroscopy–yesterday-today-and-tomorrow(4ee74946-0af7-4621-9b56-e7a2f6269bae)/export.html) indicates that things may have indeed progressed well after the 2006 reference:
THz spectroscopy exploits the farthest region of the infrared, at very long wavelengths. In this interesting spectral range we observe fingerprint spectra of explosives and other solid chemicals, we observe the interplay between molecules in the liquid phase, and we observe the motion of electrons in semiconductors. Bordering the microwave and optical regime, the THz region has traditionally been difficult to access. Recent technological developments have changed this, and today portable, high-performance spectroscopy tools for investigation of the THz range is available. In this presentation I will briefly outline the technological challenge for THz spectroscopy, give selected examples of spectroscopic applications, and demonstrate portable instrumentation for THz spectroscopy and imaging.
So, let your imagination rip–there’s good science behind some far out possibilities.