Laser pointers have been around since red laser diodes look to have been on the market which means they are older than most teenagers who bought them. Laser pointers are usually made from direct diode lasers or solid state laser diodes (DPSS). Direct diode pointers available in red or violet (made from Blu-Ray lasers at 405 nm WL “nanometers wavelength”) and direct diode green are likely to be available soon thanks to a company called KAAI that develops them for the laser projector market.
Red laser pointers are available in various wavelengths such as 635 nm, 650 nm, 660nm, 670 nm.
DPSS laser pointers are usually available at the following wavelengths, (blue) at 473 nm, (green) at 532 nm and (yellow) at 589 nm and (orange) at 593 nm. Because the human eye is most sensitive to green with a clear peak brightness at 555 nm this means that all the other visible colors look less bright despite the same power level. The difference in brightness of a clear color is basically expressed in this ratio with green at 514 nm being (1) then blue at 488 nm becomes (2.6 times smaller than green) and red at 647 nm becomes (4.6 times less than green). Previous ratios and wavelengths can be found in the mixed Argon / Krypton Ion gas, a white light laser used by professional laser show companies. The color brightness ratio will vary according to the wavelength but the above given ratio will give you the right color balance of white light. To summarize the 1 watt green laser at 514 nm it seems as bright as a blue laser 2.6 watts at 488 nm and as bright as a 4.6 watt red laser at 647 nm. You should consult a color chart to compare the clear brightness of other laser wavelengths.
Some things to consider If you want to buy a DPSS laser pointer is the power level and the way the diode is operated. What I mean about power levels, is the actual power level measured at the operating wavelength. Because a typical green DPSS laser pointer has several laser wavelengths involved to produce twice the frequency of visible output, unless the manufacturer provides good filtering, the power you measure at 532 nm may also come from 2 other IR laser wavelengths. You can actually get cheap laser pointers that emit infrared light (808 nm and 1064 nm) almost as high as visible light, which can be very dangerous and deceive someone who thinks they are buying a house that burns paper. Another thing about DPSS laser pointers is the way the diode pump is operated, which can be pulsed (turned on and off at a fixed frequency) or a constant wave of CW (continuously). It’s easy to determine if you are buying a laser pointer DPSs are pulsating because you will see lines that are cut if you move the rays quickly across the wall or ceiling.
The last concern with laser pointers is the biggest, namely security because the ever increasing power output is available today. Usually laser pointers are limited to 5 milliwatts but there are manufacturers that seem to serve clients who want more power like Evil Lasers in China that provide pointers that are more like flashlights, producing power levels as high as 500 milliwatts of green or red. It also doesn’t take rocket scientists to buy raw laser diodes and drivers to make them themselves higher than legal laser pointers.
To provide a perspective on the power level, a 5 miliwatt green laser at 532 nm would be enough to enchant your night-adjusted vision and might cause an automotive accident to say one hundred meters from the source. Conversely, a 500 milliwatt green laser can easily cause permanent damage to your vision, ignite fires by burning paper or other combustible material at close range and inevitably distract airline pilots who approach the runway at a distance of one or two miles. Safety is everything when it comes to laser pointers.
Because laser applications are so widespread, we cannot prohibit them but try to apply better control over their use and distribution. Lasers are strictly controlled by the Food and Drug Administration, the FDA in the United States and other regulatory bodies that are related to countries that produce and sell them.
To be sure, lasers are inspired by science fiction and laser pointers attract not only fans of Trekkies and Star Wars but people from all walks of life. Be it sports enthusiasts who are eager to influence the results of home games or grandma gets her training and cheap entertainment while playing following the red dot with 10 of her cats, lasers are everywhere.
I have worked with lasers for more than 20 years. I have designed, built and operated laser projectors for more than 10 years. As a laser or laser operator, I enjoy another path to creative expression using this extraordinary media to help the charity I choose. I am also a Stained Glass artist with more than 20 years of experience.
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