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Multiple beams

RedCowboy

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There was a discussion on PhotonLexicon back in 2006 about producing a custom "axicon" optic that might be helpful to your build. (Despite the fact that there are axicon lenses, that's not what this was about.) The idea was to start with a rod with a conical tip and then grind 4 (or more) symmetrical flat faces into the tapered tip. Then cut off the tip, mount it on a backing plate, and drop the whole thing in a vacuum deposition oven to coat those flat faces with dielectric film to make them into high-efficiency first-surface mirrors.

Now you could aim an array of 4 (or more) diodes at those faces and the resulting output beam would be a tightly-packed cluster of collimated beams that were perfectly parallel to each other - no knife-edge mirrors required. There was even talk about drilling out the middle of the rod so you had room for a central beam.

The project never really went anywhere, but the physics were sound and the actual manufacturing process was fairly well described. I think something like this could still be done affordably, and it would certainly simplify any optical arrangement where you needed to combine several diodes together into a single, composite beam.

Food for thought...

Adam
We have had those ideas too and as the beam width is the limiting factor we could use cut mirrors about the width of a beam.:cool:

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See this Thread....


A More advanced version of this IS now about 50% complete !!! C-19 slowed things down !!! The name of this project is...
" The Green Kraken " Alaskan has commissioned me to design and build. I MUST get his approval to post ANY details...but...I assure you...THIS will be completed by Fall 2020....and will be Epic !! We are hopeful to deliver 10.4 W out the front door in a small beam pattern array.
Hold on to your hat !! CDBeam
@ CDBeam777 : Aligning all those beams will be challenging, can't wait to see it. :)

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CDBEAM777

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Thanx Adam...THIS is surly my most complicated build to date !!! Alignment is just going to be a real TREAT !!! And yes...we are using special cut Front Surface mirror segments to form the final array of bounce mirror's. We have a company that will grind the modified flat facet Axicon but have decided to pursue a POC with discrete FS mirror segments. EPIC BUILD !!
 

RedCowboy

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I was thinking about a host with two beams and how they would appear to run together as the beams diverged if you put the bars horizontal, then I thought about using 2 of these 3 mode drivers I found for 4 dollars each and they always step through the same but the strobe is slightly different which gives a near effect.
This is a test bed, will put in a host later.

As one strobe rate catches up to the other and then gets 180 out, at 180 out it appears to shimmy, looks better live of course.

1600658777485.jpeg



Too much fun.

 
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RedCowboy

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I know a knife edge array will be the way to go, when I get enough 7A75's, HR reflectors and c-lens pairs, one for each beam then I plan to build one in a nice thick aluminum box......but this is fun and I am able to get really good far field convergence by adjusting the lens in the lens barrel to module thread slack under my lens locks. This is just a prototype, a finished build would be cleaned up/enclosed.

There are nubm05's from my block, pretty strong @ 3.5A doing 5W w/G2 and 4W w/3E .....I would use 7A75's in a finished build, yes I will add 2 more beams soon, just having fun.

The paper tubes hide any lens flair giving me clean looking beams, my holes are so close that only 1 roll of paper will fit between modules.

Because the spot/bar becomes wider than the spacing between my modules the beams appear to run together from about 20 meters to infinity in a bar shaped spot just like we see with a single beam in the far field.

It's raining and that's a rain drop seen in the left beam.


Perspective is something I need to remember when talking beam footage, here you can see how close together the beams are, starting close and as the beams diverge you cam make a single plane multi beam work in a hand held because of how our visual perspective works, I am simply raising my camera up in my hand to show the perspective, I should take some coming and going beam shots too.
The lens flair hiders made of rolled paper really clean things up huh ?





SANY5554.JPGSANY5559.JPGSANY5561.JPGSANY5571.JPGSANY5596.JPG

SANY5585.JPG
 
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