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Sun Laser

Xplorer877

Xplorer877

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Ok first off I know that this does not qualify as a "laser", and that sunlight diverges. However, if perhaps the small lens that focused the sunlight into a approximate beam was exactly right I would imagine that if this thing was big enough it would be pretty powerful. A glass lens 2 feet in diameter would be hard to find and expensive, but maybe a Fresnel lens would work. The smaller concave lens would have to be glass.
 

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Switch

Switch

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And would be good at annoying people at a distance , heating up stuff, and melting plastic at a smaller distance, but forget about melting pennies and burning wood. :p
 
Cyparagon

Cyparagon

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Sunlight wouldn't have too bad of divergence, actually. Given the earths distance from the sun, any two rays are virtually parallel with each other. A wild guess would be 5-10mRad.
 
Xplorer877

Xplorer877

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randomlugia said:
http://www.solardeathray.com/

It's a good idea, but it would be hard to find the right lenses. What exactly is the wavelength of sunlight?
Click to expand...


Sun light is a mix of all wanelenghts from radio to gamma rays. But our atmosphere filters out most of the dangerous higher energy waves.

I know it wont put a hole in steel even if it's two feet in diameter, but if one was to account for some divergence in the focusing lens and have it properly aligned I would imagine it will easily set fire to paper at a distance.
 
H

hydrogenman15

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Sun light is not coherent. :p It simple can not be turn into a laser like
that. We've been through this before.

--hydro15
 
S

sad_sagi

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i'm sure with enough lenses you could get the sun's beam kinda in a line...
speaking of which i really want to get a fresnel lens... maybe they will be cheap in winter cause theres not much sun haha.
those things are effing scary btw
turning cinder blocks glowing orange...
:eek:
 
randomlugia

randomlugia

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What's a fresnel lens? Wikipedia makes it confusing. :eek: Is it just a giant magnifying glass? Because I have a giant 1.5' across one. ;D
 
Dark_Horse

Dark_Horse

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This month's Scientific American has an article about a Japanese-project to create a huge space-based solar-laser that would project a large (50' I think) spot down to the ground, where it would be collected by a solar-farm. They describe a ground-based "proof of concept" laser that they are using right now, they are getting over 800watts from it, now.
Whatever they are using to lase the sunlight should be available to us in the coming years, (it does say in the atricle what they are using, I just cannot remember)
 
C

cybob101

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Switch said:
[quote author=simplysped2 link=1225885183/0#2 date=1225895493][quote author=Switch link=1225885183/0#1 date=1225889922] forget about melting pennies and burning wood. :p
Click to expand...
*cough*
http://www.youtube.com/watch?v=8tt7RG3UR4c
[/quote]
The metal is directly in front, and very close to the lens.And that's not exactly a 2 feet fresnel lens, either. ::)[/quote]

um i have a 15"by 15"(inch) fresnal and i can set fire to wood in less than 3 seconds
 
H

hydrogenman15

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Guys, do I we really need to go over this again. The suns light is not coherent so
the waves are going in all sorts of different directions so it can't really be focused
into a beam like a lasers light can.

--hydro15
 
RA_pierce

RA_pierce

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randomlugia said:
What exactly is the wavelength of sunlight?
Click to expand...

Ha!

All of them.



Sunlight is coherent compared to an incandescent light bulb.
It can be made into a reasonably "parallel" beam, just not effectively as a laser.
The rays aren't scattered as with any other light source, they at least travel uniformly in one general direction.

I really don't see a point in making it into a parallel beam though.
A fresnel lens works just fine as is. Adding optics and mirrors just adds on to the cost and reduces power. And that defeats the purpose of having easily attainable, low cost, large area fresnel lenses.
And is all the frustrating alignment worth the seared flesh and corneas?

If you want to do some "long distance" burning with the sun, get a large parabolic mirror with a long focal length.


The End.
 
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