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Regular green laser pointer used to detect hazardous chemicals

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October 11, 2012

A consumer laser pointer has been used to create a small, inexpensive Raman spectrometer (...

A consumer laser pointer has been used to create a small, inexpensive Raman spectrometer (Photo: Shutterstock)

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Hand-held laser pointers can now be used for something else besides doing presentations, projecting images of microorganisms, and disabling satellites. Next week, a group of scientists from Israel’s Ben-Gurion University of the Negev will be presenting a compact device that they created, which uses a garden-variety green laser pointer to detect dangerous substances such as explosives.

The device is a particularly small, inexpensive version of a Raman spectrometer.

These work by shining a highly-focused beam of light, at a specific wavelength, onto a sample of material. That material scatters the light. While most of the scattered light retains its original qualities, some of it experiences a shortening or lengthening of its wavelength, which is caused by the unique properties of the material. By detecting this altered wavelength and then comparing it to that of the originally-emitted light, the spectrometer is able to identify what chemicals are present in the sample.

While such spectrometers can be relatively large and expensive, the use of the consumer-grade laser pointer helped bring down the size and cost of the Israeli device – it also decreased its power requirements. Additionally, the laser’s short wavelength reportedly makes it easier for the device to detect the scattered light.

On top of that, the spectrometer is able to perform an initial optical scan of the entire sample, looking for areas of interest to analyze with the laser. Ordinarily, such a task would have to be performed using a separate Raman microscope.

Schematic drawing of the Raman spectrometer, including a laser pointer, dichroic mirror, p...
Schematic drawing of the Raman spectrometer, including a laser pointer, dichroic mirror, prism, objective, x,y motorized translational stage, long wavepass edge filter, lens and a detector

“Since the overall system is modular, compact, and can be readily made portable, it can be easily applied to the detection of different compounds and for forensic examination of objects that are contaminated with drugs, explosives, and particularly explosive residues on latent fingerprints,” said Ilana Bar, a researcher on the project. “With proper investment, this system could be deployed quite quickly as a consumer product.”

The Ben-Gurion scientists will be presenting their research next Thursday in Rochester, New York, at Laser Science XXVIII - the American Physical Society Division of Laser Science’s Annual Meeting.

Similar systems are being developed by BioPhotonic Solutions and Princeton University.

Source: The Optical Society

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth
4 Comments

Using a 30 dollar laser pointer is probably offset by the use of a 30,000 dollar intensified ccd.

matter13
11th October, 2012 @ 05:18 pm PDT

matter13, then why did the article writer Ben not say so? While such spectrometers can be relatively large and expensive, the use of the consumer-grade laser pointer helped bring down the size and cost of the Israeli device, hint nudge, I have a 445nm laser

Bill Bennett
11th October, 2012 @ 10:21 pm PDT

Another capacity of the Tricorder falls into place ...

Brian Hall
12th October, 2012 @ 05:58 pm PDT

Why did you used a green (445 nm laser) ? By using red one you could improve the resolution by means of the number of diodes per mm in CCD array.

Karol Luspai
31st January, 2014 @ 06:52 am PST
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