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What power will allow a visible beam?

paul1598419

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Congratulations on your 9000th post, diachi. I'm creeping up on 8000 myself. :yh:
 

green lasers rock

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Congrats, won't be long to 10k now :)

If I had a mw for every time you posted, I'd have a severely overdriven nubm44!
 
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hakzaw1

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also
of the several ways to observe...
coming at you (overhead hopefully) the beams are easier to see.
OR looking from behind is also good.
From the side.. it takes more power-a 'brighter wavelength' and/or something in the air.

for reds, 635 to 640 show up the best even tho 650 seems to be about the same on paper... there is a vid on the other forum (by vet 'Norty') of two identical red projectors and the 650 at 4000mW is about the same to our eyes as just 2W of 640 (afaik the most expensive red dodes too)
 

steve001

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For a standard 650 nm red laser, what's the general rule for power necessary to produce a visible beam? I'm not talking a lightsaber, just something that will distinguish it from a dog toy. I'm very skeptical of buying 30mW for a build and being able to see the difference.
Your question is far too vague to give a simple answer. Under what conditions will you be using this laser?
 

Encap

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Your question is far too vague to give a simple answer. Under what conditions will you be using this laser?
Exactly--it is a meaningless question -- there is no visible laser "beam" in a vacuum regardless of power 1/10W or 1MW no visible beam---a visible beam is a function of reflections possible in a given atmosphere
 
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hakzaw1

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not to mention trying a search first.
..:wtf:

. weird question.:whistle:
 

green lasers rock

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To Be fair this is an old post, White Fang hasn't been online since 10/17. Still, laser visibility information is fairly common.
 

Raybo

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It depends on how clean the air is too.

In a smokey room even a 5 mW 650 nm laser will produce a visible beam, but in cleaner air much larger power levels will be required.

In pure air, with no particles floating around etc, you can see a beam only due to scattering at a molecular level. This effect is -very- small. If you were standing in a well lit cleanroom there could be a 10 watt green beam passing a meter in front of your eyes without you noticing it at all, since there is nothing 'big' in the air to scatter that light and ambient light is so bright it will swamp out any molecular level scattering easily.
/\ This
 

paul1598419

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Frank Zappa?! Been a long time since last I thought about him. :crackup:
 

Raybo

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BTW.

Frank has been my avatar since I joined LPF in '08.
 
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paul1598419

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No doubt. "Don't go where the huskies go and don't you eat that yellow snow." Nanuk of the North.
 

paul1598419

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Oh, that wouldn't get you banned. "Torture Never Stops" is tame by Zappa standards. Do you remember, "If she were my daughter...." "What would you do, daddy?" "Well,if she were my daughter....." "What would you do, daddy?" "I'd cover that girl in chocolate syrup and boogie 'til the cows come home." Man, there were so very many like that.
 

diachi

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Oh, that wouldn't get you banned. "Torture Never Stops" is tame by Zappa standards. Do you remember, "If she were my daughter...." "What would you do, daddy?" "Well,if she were my daughter....." "What would you do, daddy?" "I'd cover that girl in chocolate syrup and boogie 'til the cows come home." Man, there were so very many like that.
Man, I knew you had to be a Zappa fan. I imagine you have quite the taste, we'll need to share some music some time. :D
 




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