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Tests Show Many Laser Pointers Giving Off Excessive Power

Laser beam pointed at camera (Nayu Kim)In tests by researchers at National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland, many laser pointers on the market, including most pointers with a green beam, emitted more power than allowed by federal regulations. The team led by Joshua Hadler, NIST’s laser safety officer, reported on the tests today at the International Laser Safety Conference in Orlando, Florida.

NIST is a non-regulatory agency of the Department of Commerce that provides guidance to industry, academia, and other government agencies on laser power measurements based on international standards. NIST provides its data on laser pointer power measurements to the U.S. Food and Drug Administration, which regulates laser product safety.

The team from NIST tested 122 laser pointers and found that three-quarters of the green pointers and almost half (44%) of the red pointers tested were out of compliance with federal safety regulations. The tests show both types of pointers emitted more visible power than allowed under the Code of Federal Regulations, with green pointers also often emitting infrared light at unacceptable levels. Green pointers generate their green colored laser from infrared light.

Hadler and colleagues randomly sampled laser pointers labeled as safe for use in classrooms and other public spaces, which are limited to 5 milliwatts maximum emission in the visible portion of the spectrum and less than 2 milliwatts in the infrared portion of the spectrum. American National Standards Institute, a voluntary standards organization, notes that laser devices that exceed the limits for these types of devices may be hazardous and should be subject to more rigorous controls such as training, to prevent injury.

The tests showed half of the devices tested emitted power levels at least twice the legal limit at one or more wave lengths. The researchers say the highest measured power output was 66.5 milliwatts, more than 10 times the legal limit.

Hadler designed the laser measurement technology to be easily implemented by manufacturers. The testing system has a laser power meter and two optical filters to quantify the emissions of different wave lengths of visible and infrared light. Both the power meter and filters were calibrated at NIST. “The measurement system,” says Hadler, “is designed so that anyone can build it using off-the-shelf parts for about $2,000.”

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Photo:  Nayu Kim/Flickr

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