Green laser pointers have become popular presentation tools since they deliver light that’s brighter to the eye than red lasers. NIST researchers purchased three low-cost green laser pointers advertised to have a power output of 10 milliwatts (mW). Measurements showed that one unit emitted dim green light but delivered infrared levels of nearly 20 mW — powerful enough to cause retinal damage with no indication of a potential problem. NIST’s Jemellie Galang and her colleagues repeated the tests with several other laser pointers and found similarly intense infrared emissions in some but not all units. According to the research teams, the problem stems from inadequate procedures in manufacturing quality assurance.

NIST provides detailed  instructions for a home test at www.nist.gov/customcf/get_pdf.cfm?pub_id=906138 that laser hobbyists may conduct with proper safety precautions to detect excessive infrared leakage from a green laser pointer. The test requires a digital or cell phone camera, a compact disc, a webcam and a TV remote control. It must be emphasized that green laser pointers should never be directed at the eyes or aimed at surfaces such as windows, which can reflect infrared light back to the user.