As NIST researchers reported at a conference on March 20, 2013,* both red and green laser pointers often emitted more visible power than allowed under the Code of Federal Regulations (CFR), and green pointers often emitted unacceptable levels of infrared light as well.
Anecdotal reports of green laser hazards have previously appeared in scientific journals and the media, but the new NIST tests are the first reported precision measurements of a large number of handheld laser devices. The NIST tests point out that many red laser pointers are also—unexpectedly—out of compliance with federal regulations. "Our results raise numerous safety questions regarding laser pointers and their use," the new paper states.
The NIST 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 milliwatts maximum emission in the visible portion of the spectrum and less than 2 milliwatts in the infrared portion of the spectrum. About half 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 milliwatts, more than 10 times the legal limit. The power measurements were accurate to within 5 percent.
According to the American National Standards Institute (ANSI), laser devices that exceed 3R limits may be hazardous and should be subject to more rigorous controls such as training, to prevent injury.**
NIST is a non-regulatory agency with decades of experience providing industry, research and military agencies with laser power measurements traceable to international standards. NIST also has a history of innovation in devices for making such measurements. Technical staff from NIST's Laser Radiometry Project built the laser pointer test bed and collaborated with the NIST Office of Safety, Health and Environment on the tests. NIST has provided its data on laser pointer power measurements to the Food and Drug Administration, which regulates laser product safety.
Green lasers generate green light from infrared light. Ideally, the device should be designed and manufactured to confine the infrared light within the laser housing. However, according to the new NIST results, more than 75 percent of the devices tested emitted infrared light in excess of the CFR limit.
NIST Laser Safety Officer Joshua Hadler designed the measurement test bed.*** The system consists of a laser power meter and two optical filters to quantify the emissions of different wavelengths of visible and infrared light. 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 $2,000," Hadler says. "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."* J. Hadler. Random testing reveals excessive power in commercial laser pointers. Presentation at the International Laser Safety Conference, Orlando, Fla., March 20, 2013; J. Hadler, E.L. Tobares and M. Dowell. Random testing reveals excessive power in commercial laser pointers. Journal of Laser Applications. (Forthcoming.)
Laura Ost | EurekAlert!
Smallest transistor worldwide switches current with a single atom in solid electrolyte
17.08.2018 | Karlsruher Institut für Technologie (KIT)
Protecting the power grid: Advanced plasma switch for more efficient transmission
17.08.2018 | DOE/Princeton Plasma Physics Laboratory
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
17.08.2018 | Physics and Astronomy
17.08.2018 | Information Technology
17.08.2018 | Life Sciences