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FrozenGate by Avery

Beam Expanders ---

Hemlock_Mike

Hemlock_Mike

0
Joined
Jan 7, 2007
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Beam expanders are so easy to build and what they can do is amazing.
Here is a 2.5x expander I just built tonight using a simple telescope from DX. This is on an old 1 Watt 445 nM I built long ago.

6015-expand3.jpg


and here's the one I built which fits both the Arctic and Krypton. It is about 3.5x.



HMike
5998-expand2.jpg
 
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Nice. What have you done to attach it to the laser ?
This expander will work, but I sure a lot of light is lost do to poor transmission of light and reflections off the multiple lens surfaces.

How about some outside before and after pics of this expander in action ?
 
rocket689 said:
Heehee. I love playing with high powered lasers and telescopes. :D
Click to expand...

lol! i have an old 60mm refractor (about 3 ft long LOL) i connected my 400mw greenie to, and i send a fairly bright 3 inch diameter beam into the sky :evil:

i think my neighbors are afraid of me...
 
what parts did you use and how were they arranged? i have a few telescopes and binoculars.
 
cheech226 said:
what parts did you use and how were they arranged? i have a few telescopes and binoculars.
Click to expand...

Using an intact refractor telescope, binocular shine your laser into the eyepiece. Read up on Galilean beam expander.
 
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cheech226 said:
i didn't realize the theory was that simple. got a new project..
Click to expand...

Here's a very useful app for making beam expanders
gausian beam rev 2.0.xls
It has a text presentation along with a graphical presentation. The graphical portion is designed to be used with Internet Explorer, but it may work with other browsers equally well.
The site has other apps which may be useful
 
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Funny the OP never responded to his thread but whatever.
I just want to make my beam expand like a focused mag light flashlight. 10 or 20 ft. spread at a distance would be really cool.
I have some bi-nocs but Im not sure the lens is all glass. Dont want to melt it. Thrift shopping for lenses to play with.
 
Steve --
That is a great tool --- I played with it for a while and it is fun.
I use a neg input lens to shorten the assembly and this program looks good.
HMike
 
Hemlock_Mike said:
Steve --
That is a great tool --- I played with it for a while and it is fun.
I use a neg input lens to shorten the assembly and this program looks good.
HMike
Click to expand...


A Galilean beam expander has the shortest practical working distances. Compare that to a Keplarian beam expander which has a practical working distance between the lenses equal to the sum of each lens. I think you noticed that.
What I like most of all is it gives the Rayleigh Range, not just the beam size and beam divergence.

You are the first person that's ever said they like it. :-)
 
So I have an 8inch mirror telescope. Can I get similar results or do I have too many obstructions in the tube?
 
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