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FrozenGate by Avery

Multiple Diode laser

T

The Incident Photon

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Me and some of my collegues are thinking about creating a laser that features more than 1 diode. Where planning to achieve this by placing the diodes at the back of a large host and then using mirrors to direct each of the diode beams into a master pump focusing lens producing a stronger, more visible beam. I need to know if this has been attempted before or personal opinions on the matter.
 





This is easy enough to do, check out the 4.4W build (in my signature) or the reference guide to combine lasers (also in my signature).

If you're using two diode of the same wavelength use a PBS, if you're using more than two diodes of the same wavelength use knife edging.
You can combine two lasers of different wavelengths to make purple, yellow, orange, pink ect. with a dichroic mirror.

You can buy cheap dichros from DTR (they are in the project optics assembly) and PBS's can be found in PHR sleds, but they are pretty small.

Good luck!
 
Also, difference between knife edging and using PBS, is that the PBS can overlay two beams, while knife edging is putting beams so close to each other to appear as one.

knife edging might take four beams, o o o o, and bring them really close together: 88

PBS would take two beams, o o, and super-impose them: o

Things can be done to rotate the linear polarization by 90* without rotating the beam pattern, in order to super-impose two astigmatic beams without making a funny pattern.



Depending on whether space is an issue or not, you can also combine beams of differing wavelengths using the fact that the degree of refraction is dependant on the wavelength.
http://laserpointerforums.com/f49/rgb-beam-combining-prism-45014.html#post602144 < to give you an idea of how much space is needed
 
ARGLaser said:
This is easy enough to do, check out the 4.4W build (in my signature) ...
Click to expand...

Yeah, because that was so easy. :rolleyes:

In my opinion, beam combining is easier said than done. Its not just something you do in an afternoon.

That being said, there are good tools and devices available for making it a bit easier to get good results. Are you any good in a machine shop?
 
Machine shop...I have access to lathes and various CNC machines some of which ironically have extremely strong lasers on them. Most of them are accurate down to the 0.001 of an inch. I can create create parts in autodesk's inventor and then I import them into Mastercam for the actual milling procedure. I'm thinking about making some pretty cool hosts in the future with these things :D In response to ARGlaser I have a ready supply of polarized beam splitters. I'm thinking about making one with a shitload of blue diodes so wavelength shouldn't matter that much to me. I think I'm going to mill out my own host to use for this design, but I do like the tri-diode laser design. It will be similar to that.
 
Meatball said:
Yeah, because that was so easy. :rolleyes:

In my opinion, beam combining is easier said than done. Its not just something you do in an afternoon.

That being said, there are good tools and devices available for making it a bit easier to get good results. Are you any good in a machine shop?
Click to expand...

The concepts are fairly easy but to get the perfect alignment is always hard :p

@OP If you can, make adjustable mounts. You'll thank yourself later ;)
 
ARGLaser said:
The concepts are fairly easy but to get the perfect alignment is always hard :p
Click to expand...

There are several ways to set the alignment, one of the best solutions I have found
in my duals and other concepts im working on is to make a rig specifically for
the aligning process, using a telescope to view the dot over a great distance.

At least this way you don't have to worry about a gap forming over long range.
I used this same method for setting up the correction optics in mine, done in 2 stages.

Long tedious work, but worth the result :beer:
 
I live in Chicago so that might be a problem. I could possibly shine it at the moon and align the dot using a telescope from there. If I manage that feat I could top WL's claim of "lasers that can be seen from space" with "mine can hit the moon!" It's a good idea. I'll probably do this somewhere in southern Illinois where there's just cornfields and long stretches of road.
 
Is it possible to use 3 PBS to overlay 2 beams that have been already overlayed? As so:


x7f4nym.png
 
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no.. you can't use a pbs cube to combine beams that have already been combined with a pbs cube.

your best bet to combine a bunch of 445 diodes is to knife edge two arrays, and then combine the arrays with a pbs cube.

a friend and i built a 10x445 laser that way:


petters said:
Is it possible to use 3 PBS to overlay 2 beams that have been already overlayed? As so:


x7f4nym.png
Click to expand...
 
I realize this thread is a year old now and instead of making a new thread on the same subject, as I was tempted to do, but searching the forum instead so as not to be thoroughly whipped about by a wet noodle, I'm adding a question here....

Why not just take the same route that FAP diode bars do and put several diodes on a single piece of metal with their raw unfocused outputs all shooting out together into a common lens to collimate the light into one beam?

I am imagining this is difficult to accomplish because the ~ light waves would not line up peak to peak and would be subtracting and adding in and out of phase (if individual diodes are used with imprecision or varying mounts) to reduce the amount of collimated light as well as producing several other undesired effects... or can it be done without much problem? Has anyone tried to do this?
 
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Cool videos, thanks. Has anyone taken the uncollimated output of several diodes and put a huge lens in front of it so the light from each diode falls on the single lens to be collimated together with the others to make a single beam output? These videos show the laser beams combined together after collimation, I want to know if the power can be combined prior to collimation or before going through a lens? Perhaps this isn't done because the net power isn't enough to make it worth it due to cancellations from out of phase lightwaves?
 
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The angle at which the uncollimated beams enter the lens should alter the angle at which they leave the lens. So unless you could have all the lasers in the same physical spot, no.
 
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