Using Lasers to Find Land Mines and IEDs

http://spectrum.ieee.org/semiconductors/optoelectronics/using-lasers-to-find-land-mines-and-ieds/0

by jcr • 13 years ago

20 12 13 years ago

spectrum.ieee.org

nemo• 13 years ago

If I were an Afghanistani/Iraqi/whoever planting IEDs/mines trying to defeat this, I'd make small bundles with explosives in them and sprinkle them in random areas to create large enough numbers of false positives to make using this onerous.

Still, this is a promising sounding tech. for detecting mines in past battlefields, ordnance, mercury and so on. Hope the idea is developed in a workable way.

jcr• 13 years ago

It seems you're limiting your perspective to recent conflicts. Mines and unexploded ordinance are a huge and long-standing problem across the globe. For example, it is still common for explosives from the first world war, a 100 years ago, to be found in Europe. Similar is true for nearly every other conflict in history.

An interesting point the article did not mention is how some forms of munitions tend to release more identifiable gases as they slowly decay over time. This is one of the reasons why using trained dogs has been effective to locate mines. If they can get this laser and radar tech working effectively, it stands to reason this tech will be especially useful for finding and clearing old mine fields.

Mines are a terrible problem, but tech like this has a chance of saving a lot of innocent lives.

Wingman4l7• 13 years ago

There's been a lot of success in using trained rats to detect landmines -- they're cheaper to care for / transport, quicker to train (IIRC), and too light to set off the mines.

I've also read of more unusual / interesting detection techniques researched, like bees, and my personal favorite, the seeding by air of bioluminescent bacteria that feed off of said gases.

michael_h• 13 years ago

If you plant a 'small bundle with explosives', then that isn't really a false positive, is it?

bonzoesc2• 13 years ago

If you're looking for deadly munitions and you find just a scrap of raw explosive compound without any mechanism to explode it and make it deadly, that's a false positive.

unwind• 13 years ago

So, basically they're creating a lasing region of space, in mid-air, at a distance of 30 meters (~100 feet):

The beam is transmitted through a lens that focuses it on a spot 30 or so meters away; there it converges and then diverges, giving this region an hourglass shape. Because the laser pulse is very brief—on the order of nanoseconds—the intensity is high enough to break molecules of oxygen into their constituent atoms over a few millimeters in the thin midsection of the hourglass. This happens so rapidly during the pulse that the same pulse subsequently excites many of the oxygen atoms into a high-energy state, creating what's called a population inversion. This unstable condition then leads to the familiar laser chain reaction in which an excited atom drops to a lower energy state, emitting a photon of a particular wavelength, and that photon in turn stimulates another excited atom to emit a photon of the same wavelength and phase.

The thus excited region of space emits two laser beams, one in the direction of the original "trigger" beams, and one in the opposite direction i.e. back at the source. The intensity is said to be around 1,000,000 times that of the ambient radiation in that wavelength, so it's "easy" to detect. And the beam carries information about the molecular mix in the generating volume of space, which is of course the core feature here.

That is ... pretty close to being magic, in that "naah, that can't be possible!" way that is so fantastically neat.

Too bad the triggering impulse (heh) to develop this is something as nasty as land mines and IEDs, the technology itself is just beautiful.

lallysingh• 13 years ago

Sure, but how do you get the sharks 100 feet up? And won't they suffocate without water?

tocomment• 13 years ago

That's pretty amazing! I've always wondered if you could have a device that detects ice (using lasers, or other optical methods) and place one looking down at the road in front of each tire.

Your car could then warn you when it starts seeing ice, and possibly even take measures to improve control.

I know a lot of times the road will be wet and it will be below freezing but there's no ice, but it's scary to drive because you know you could encounter ice at any time.

gwright• 13 years ago

All they need to do is scale this up a bit, put it in orbit and they've got Star Trek sensor arrays.

Using Lasers to Find Land Mines and IEDs

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