The Times West Virginian

Community News Network

March 26, 2013

Slate: Your laser pointer is probably illegal

(Continued)

Lasers of this magnitude can potentially cause irreparable damage to the human eye. When focused on the retina, they yield more power density than looking at a welding arc.

What's more, green laser pointers in particular fire off a considerable amount of infrared signal in addition to visible light. The human eye is far less sensitive to infrared, which means it can't protect itself by automatically closing like it does with bright, visible lights. Even though you can't "see" it, infrared can still mess you up.

"The damage mechanism that occurs is thermal," Hadler says. "The tissue can't dissipate the heat fast enough, and it burns." In order to prevent accidental eye scorching, Hadler developed a relatively cheap, easily replicable test bed. He hopes other institutions from universities to corporations will build their own test beds to make sure their lasers are within the appropriate safety thresholds.

The NIST study shows only 26 percent of the laser pointers tested met industry standards. That means you'd do well to avoid drawing the ire of that weird little cousin — you know the one — especially if his cat-torturing device is green. A whopping 90 percent of green laser pointers in the study were not in compliance with the CFR regulations, compared to 44 percent of the reds.

"Twenty years ago, the technology required to generate this particular wavelength of laser light was a $30,000 piece of equipment that lived in a laboratory," Hadler told me. "And now for $10 you can put one in your pocket."

Of course, over-the-counter laser pointers are just the tip of the photonic spear. For $400 and an Internet connection, you could be the proud owner of a 1,250 milliwatt, Class 4 Arctic Laser "strong enough to burn holes, pop balloons, and start fires from across the room." (FYI: Such lasers should not be operated without safety goggles and a healthy respect for retinal burns. Also, beware of the Moscow rave scene.)

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