Thursday, November 17, 2011
Laser Pointer Safety
Many of us use laser pointers for improving our presentations here on campus. Until recently, laser pointers were limited in power output, typically less than 5 milliwatts (mW). Now, there are low-cost, small devices available that operate at levels 50 to 1,000 times this power, and they look just like the low-powered items. (I found a 30 mW pointer for $16, on line, and a 100 mW for less than $60!)
Some of these units emit invisible light (infrared) as well as their visible light. You can probably imagine the danger inherent in products that produce very powerful, invisible radiation.The units are often marketed as "Hand-held lasers" or "scientific devices" to get around regulations addressing "laser pointers," though I have seen items at powerful as 200 mW being labeled "laser pointers".
A laser emitting even 50 mW can immediately cause an injury which can permanently affect one's eyesight. A 200 mW laser can cause permanent eye damage in less than the time it takes to blink one's eye, from even as far as 100 yards away.
All laser devices sold in the US must have their Class noted on the unit, along with the power. Look at the labels on any laser pointers you may have. Do not purchase or use items with power over 5 mW or ones labeled Class 3B or 4. And certainly keep these items away from children.