Blu-ray Laser Gadget
i4u writes, "Wicked Lasers has done the unthinkable. They took the sparse blue laser diodes used in Blu-ray Disc drives and are making cool laser gadgets out of them, called Sonar. You can own one of these very limited edition lasers for $1,999.99. The price is that high because Wicked Lasers buys Blu-ray Disc players and removes the Blu-ray diode for the Sonar laser."
Can someone explain the importance of a blue laser over a regular handheld red laser of the same power that sells for ~$20?
It's blue.
Blue is cool. Also, hard to do. Between the two, you get expensive.
Red lasers are cheap because they're cheap to make, though the suspiciously cheap ones are, indeed, suspiciously cheaply made. Green lasers are pretty close to the human eye's peak responsiveness, so they appear brighter at a given power level than red or blue lasers.
There are all manner of lasers. CO2, Argon, and other gas lasers. Chemical lasers. Diode lasers. And several other varieties. Hand-held (and small bench) lasers are commonly diode lasers. Low-power red laser diodes are approximately free, which is why they show up everywhere. Infrared laser diodes aren't terribly expensive, even fairly high-powered ones. There is no such thing as a green laser diode. Hand-held green lasers are DPSS lasers, in which a high power infrared laser blasts a fancy neodymium compound that outputs a different infrared frequency that in turn hits a frequency-doubling crystal which finally outputs 532nm green light.
The take-home message here is that blue laser light is hard to get so it's expensive. It's also not terribly useful unless you actually need the high frequency for denser data packing. Green laser light is harder to get than red laser light, but in addition to looking cool it legitimately is more visible per watt. Check out the CIE luminosity function - 650nm red light appears about 8x dimmer per watt than 532nm green light. A $100 15mW green laser therefore should appear almost as bright as a $200 200mW red laser. Even though production of green laser light is less efficient than production of red laser light, the green laser should consume somewhat less power than the red one.
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