Better be shoving along. Brother Buzz.
Twenty years ago, a green laser would set you back $100,000 and occupy a good-sized dining room table. Today, you can buy a green laser pointer the size of a ball point pen for $15.
These devices create coherent green light in a three step process. A standard laser diode first generates near infrared light with a wavelength of 808nm. This is focused onto a neodymium crystal that converts the light into infrared with a wavelength of 1064nm. In the final step, the light passes into a frequency doubling crystal that emits green light at a wavelength of 532nm.
All this can easily be assembled into a cigar-sized package and powered by a couple of AAA batteries.
The result are devices generally advertised to have a power output of 10mW.
Today, Jemellie Galang and pals from the National Institute of Standards and Technology and the University of Maryland say they’ve found worrying evidence that the output of some green laser pointers is much higher and more insidious. They describe one $15 green laser pointer that actually emits ten times more infrared than green light.
Galang and co are under no illusion as to the potential consequences of this. “This is a serious hazard, since humans or animals may incur significant eye damage by exposure to invisible light before they become aware of it,” they say.
