Laser Pen Lights & Safety

Laser pointers and laser pens are used for a variety of reasons, from highlighting material in the classroom to improving aim with air-soft guns. Beams projected from most laser pointers present little danger to the eyes.

Red/Orange Lasers

Red and orange lasers are the simplest because laser diodes are available in these color wavelengths. First generation red lasers were sold in the early 1980s for hundreds of dollars and used to be bulky devices. You can find red lasers today for a fraction of the original price and size.

Yellow Lasers

Yellow lasers emit at a 592 nm wavelength to produce a yellow beam. However, the complex engineering behind the laser machine makes the laser pointer very unstable and inefficient. Their outputs can fluctuate from 1mW to 10mW depending on temperature. Consequently, these laser pointers sometimes require thermostat controls that can inflate the price of the device.

Green Lasers

Green lasers appeared on the market in 2000 and were a big hit, considering their complexity and high price tag. An indirect process is used to generate the green laser since laser diodes are not available in the green wavelength. Specifically, a high power IR laser diode at 808 nm pumps a tiny block of Nd:YVO4 generating light at 1,064 nm, which feeds a KTP intracavity frequency doubler crystal to produce the green beam at 532 nm. Green lasers are also special because you can see the laser beam. The 5mW green laser is also the safest of all lasers.

Laser Applications

Lasers are most popular in the education environment. They are used to highlight or divert attention to special presentations and visual demonstrations. They are also used in amateur astronomy, hiking and outdoor activities, and for military purposes. Accurately aligned lasers can be used to aim gunsights more accurately. Lasers are also used for entertainment purposes.

Laser Safety

Direct laser contact to the eyes can result in retina damage. The U.S. FDA determined that Class IIIa lasers could cause injury to the eyes if viewed directly for approximately 0.25 seconds, although it has cited evidence that exposure to visible lasers is "usually" limited by the blink reflex of the eye, which has been timed at just under 0.25 seconds. Viewing a laser pointer beam for more than 10 seconds can be harmful.

References

• Laser Types
• FDA