Cheap lasers using LED?

userx

Newly Enlightened
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Jan 26, 2005
Messages
32
Hmm, I think that I read somewhere (Sam's laser guide i think..) that cheap LED lasers are available. They supposely use a LED to some lens to focus the light to a small beam. Of course, this way it's not really a *true* laser with a spead of 10-20 degrees (very very huge) and not as powerful. But at close range, it should be somewhat decent, not to mention cheap and cool (since you'll be able to get all different colors). Hmm..but as of googling and yahooing...I still can't any places where they sell these things. Do they even exist? /ubbthreads/images/graemlins/frown.gif
 

Raccoon

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Dec 17, 2004
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630
I'm pretty sure lasers on eBay use laser diodes.

The difference being that laser diodes have a bandwidth of 1~2nm while an LED may have a bandwidth of 50~80nm (guessing).

While it may not seem like a large difference, that bandwidth will determine the distance that the light is cast. The larger the width of the light spectrum, the faster it will neutralize itself as the photons stop "marching in unison" and start "shooting eachother".

At least, that's how I understand it.
 

PhotonWrangler

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A laser diode's bandwidth-vs-current curve is interesting. Turn the current down to just below lasing threshold and the bandwidth suddenly spreads out as it acts like a regular LED. This phenomenon is actually a problem in systems that use direct AM modulation of the drive current, and shows up as laser "chirp."
 
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