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 Laser Pointers Negative divergence... cant be this simple...

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09-14-2007, 06:10 PM #1
 Class 2 Laser Join Date: May 2007 Posts: 340 Rep Power: 14
Ashton
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Negative divergence... cant be this simple...

How does one go about setting up a lens for negative divergence? The reasoning in my head says you just need a convex lens mounted at the right distance from the LD... I know it cant possibly be this simple though...

09-14-2007, 07:10 PM #2
 Class 2 Laser Join Date: Aug 2007 Location: St Louis Posts: 341 Rep Power: 97
laserrod
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Re: Negative divergence... cant be this simple...

Just put your collimater lens closer to LD than the lens Focal point.
That makes beam waist converge to a point.

If you can find a longer focal lenth Collimater lens the beam waist will be bigger but spead less over distance. KEYWORD: miliradians.

If your laser is spec. .8 milliradians beam spot at 1000 meters is .8 meter diameter. (.0008 X 1000 = )

Hope I didn't write that backwards. ;D ;D

Cheers [smiley=beer.gif]

09-14-2007, 07:17 PM #3
 Class 3R Laser Join Date: Oct 2006 Posts: 2,032 Rep Power: 32
pseudonomen137
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Re: Negative divergence... cant be this simple...

Negative divergence? What do you mean by that one? You mean getting the beam to converge to a focus? If you have a collimated beam, you just move the lens a little further from the source, and it will bring it to a focus.

09-14-2007, 07:20 PM #4
 Class 2 Laser Join Date: May 2007 Posts: 340 Rep Power: 14
Ashton
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Re: Negative divergence... cant be this simple...

wow it really is as simple as I thought...... so what was so special about WL's pulsar having a negative divergence then? I thought it must have took osme huge engineering marvel to create it or soemthing... what's the big deal?

09-14-2007, 11:20 PM #5
 Class 3R Laser Join Date: Jun 2007 Posts: 1,808 Rep Power: 386771
steve001
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Re: Negative divergence... cant be this simple...

Quote:
 Originally Posted by Ashton wow it really is as simple as I thought...... so what was so special about WL's pulsar having a negative divergence then? I thought it must have took osme huge engineering marvel to create it or soemthing... what's the big deal?
Sounds like another WL ploy on the unsuspecting buying public

09-15-2007, 05:44 AM #6
 Class 2 Laser Join Date: May 2007 Posts: 340 Rep Power: 14
Ashton
Class 2 Laser

Join Date: May 2007
Posts: 340
Rep Power: 14
Re: Negative divergence... cant be this simple...

well, yes and no, this one I cant fault them on, because it really IS unusual, however they blew it WAY out of proportion...

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