Tests Underscore Potential Hazards of Laser Pointers
GAITHERSBURG, Md., and ORLANDO, Fla., March 21, 2013 — Of the 122 laser pointers tested recently by the National Institute of Standards and Technology, nearly 90 percent of the green pointers and about 44 percent of the red were out of compliance with federal safety regulations, the agency reported Wednesday at a conference on laser safety.
Using a low-cost apparatus designed to quickly and accurately measure the properties of handheld laser devices, NIST researchers found that both green and red laser pointers emitted more visible power than allowed under the Code of Federal Regulations (CFR), and that green pointers often emitted unacceptable levels of infrared light as well.
Ideally, green lasers should be manufactured to confine the infrared light within the laser housing. However, according to NIST, more than 75 percent of the devices tested emitted infrared light in excess of the CFR limit.
Many red laser pointers are also — unexpectedly — out of compliance with federal regulations, NIST said.
“Our results raise numerous safety questions regarding laser pointers and their use,” the report states.
The tests were conducted on randomly selected commercial laser devices labeled as Class IIIa or 3R and sold as suitable for demonstration use in classrooms and other public spaces. Such lasers are limited under the CFR to 5-mW maximum emission in the visible portion of the spectrum and less than 2 mW in the infrared spectrum. About half of the devices tested emitted power levels at least twice the CFR limit at one or more wavelengths. The highest measured power output was 66.5 mW, more than 10 times the legal limit. The power measurements were accurate to within 5 percent.
NIST laser safety officer Joshua Hadler and his apparatus for measuring the properties of handheld laser devices. Courtesy of Burrus/NIST.
Laser devices that exceed 3R limits may be hazardous and should be subject to more rigorous controls such as training, to prevent injury, the American National Standards Institute said.
The laser pointer test bed was designed by laser safety officer Joshua Hadler and built by technical staff from NIST’s Laser Radiometry Project in collaboration with the Office of Safety, Health and Environment. The system consists of a laser power meter and two optical filters to quantify the emissions of different visible and infrared wavelengths. The power meter and filters were calibrated at NIST. Lens holders ensure repeatable laser alignment, and an adjustable aperture contains the laser light around the output end of the laser.
“The measurement system is designed so that anyone can build it using off-the-shelf parts for about $2000,” Hadler said. “By relying on manufacturers’ traceability to a national measurement institute such as NIST, someone could use this design to accurately measure power from a laser pointer.”
Data from the laser pointer power measurements was provided to the FDA, which regulates laser product safety, and was presented at the International Laser Safety Conference in Orlando.
For more information, visit: www.nist.gov