50W 7 beam hand held?

[Benm]

It is hard to answer that for 100 feet range really.

This distance is not really near, nor really far away. I suppose knife endging the diodes would still be feasible at that range, and much easier to do compared to proper beam combining.

Another thing to realize is that your lasers are not locked to eachother by any means. Each has its own wavelegth, there is not phase locking between them or anything like that, at all.

This is vasly different from the research lasers which actually are synchronous in phase and all that.

 

[CDBEAM777]

Hmmmmm...... ???????.....Hmmmmm ????? I think the 044 is the worst LD for a multi unit project !!! RC, I am assuming there is to be NO Cylindrical lens correction used in your project ?

I speculate that the extreme emitter size of the NUBM044 will deliver such an astigmatic beam.....that at 30.48M (100 ft)....one could not focus each beam down to a what.....1mm diameter....as this picture shows. I would speculate that at 30.48M ( 100ft)....the beam geometry of a ...G2 collimated 044 LD....would be very, very wide....a SWAG....1M in width !!! Yikes.

At this optical energy density..at 30M..aspect ratio orientation/bar orientation is well...meaningless.

If one desires...to " Cut the Cheese" pizza....at 30M....one might need 50W:eg::eg::eg::eg:

Beam out

 

[RedCowboy]

Great answer Benm, the quality of these MM phosphor pumping diode beams is not sufficient for fiber combining, I doubt it matters how they stack, just get them all into a small spot for hobby use will be fun.

Yes this is one of my 44's with a G2 primary followed by 6X cyl correction and then a 3X BE just to get this at 81 feet. I was thinking about simply converging a half dozen and wondered if rotating each a little would make any difference, I doubt it will but I ask to learn.

 

[CDBEAM777]

Hmmm...looked more closely at your drawing....and pic.

Those 044 units in the pic must be cylindrical corrected....If they are....then I would say that the orientation of each " bar " should be the same to achieve maximum optical density.

By overlaying them at the Far Field....it stands to reason that a greater optical density will be realized !

Now...the combined Far Field geometry will be less like a bar shape...with the Star ( * ) arrangement....but I bet the Optical density would be lower!!!

Beam out

 

[RedCowboy]

That's what I would think, and yes it's really simple, I did put cyls in my terrible drawing, it's a 2D quickie done in paint.

I was curious if there was some possibility of wave front interference as the angle of multiple beams becomes narrower at distance, and may run together as they merge near the target when I start with everything in one box, it was a dumb question really but I thought I would ask as there could be something to it.

Thanks

Benm and CDBEAM777 I owe you both a rep, you both are a wealth of information.

 

[Light superglue]

Hi RC,

Your old setup remind me of my "Death Star" building attempt from 2007 to make a portable "torch" with 8 (eight!) 532nm modules from pointers which appeared back then on DX (200+mW or so).

All 8 ball-articulated mounts were taken from camera mini tripods - material was Al, not plastic!
But I never managed to align and fix them all even for parallel beams not talking about converging. Finally had to throw away that beauty:cryyy:

The KEdging of 4 NUBM44 I am tinkering with at the moment is just the same kind of a "Death Star" but beams have to be converged after correction in only one dimention what looks easier to me...


Edit: And there was a thread with video from a german guy who made a model of a real DS (not portable!). Here I found it:
http://laserpointerforums.com/f65/90w-blue-14-diodes-onto-one-spot-death-star-style-96177.html

 

[RedCowboy]

The 532's and 660's also 405's could be knife edged and bundled then using an expander zoomed to the point desired, but these multi mode projector phosphor pumpers are so unevenly divergent that it makes converging more attractive than combining, but even then to get any real distance each diode needs correction.

Maybe we will see some bigger single mode diodes in the future to replace pumped crystal lasers, but there is something really pretty about a bunch of beams all converging on a point, most of all be safe and happy lasing.

 

[Benm]

Knive edging a number of beams can give you a high power density at some point. You can even totally different wavelenghts to do that without any dichros and such.

It could be a really good method to set something on fire, but it -does not- combine laser beams.

 

[RedCowboy]

Yes I understand that about knife edging, but if you knife edge several beams that are diverging differently on one axis than the other, there may become a point in the far field where many beams that were side by side are now overlapping each other by quite a bit, actually the divergence of the 44 for example is so radical that even when corrective optics are used the beam expands quite a lot, so my concept is to start with say 8 lasers in a box possibly in a circle and converge them all on top of each other at the target.

Each beam would by cylindrically corrected as much as possible....actually I am rethinking using maybe 36 x BDR-209 diodes and doing some knife edging to make 6 rows of 6 because the 44 is just so aggressively divergent and the junction is quite large compared to others.

For instance at 81 feet a 6X cyl corrected NUBM44 with a G2 primary prints much like a NDB7875 with a 3 element, now closer in it's a different matter, but the 44 can be set up to start smaller, but it will out expand the 7875 over distance.

There are many reasons why using 6 times as many 405nm diodes would be better.

I think I need to construct a proof of concept and do a 9 cluster, that is 3 x 3 of 405nm diodes knife edged, it will likely be quite satisfying. Later a 36 diode 6 x 6 will be fun.

It's still academic at the moment, I need to decide just how hard the 405 can be driven for regular use.

p.s. I wouldn't mind seeing a 40w single diode any time now, granted beam specs won't be anywhere near as good as a C02, however this is just for fun and I want it to be pretty. :beer:
A 40w C02 with some trace visible lasers

 

[Project Excalibur]

Each beam would by cylindrically corrected as much as possible....actually I am rethinking using maybe 36 x BDR-209 diodes and doing some knife edging to make 6 rows of 6 because the 44 is just so aggressively divergent and the junction is quite large compared to others.

There are many reasons why using 6 times as many 405nm diodes would be better.

I think I need to construct a proof of concept and do a 9 cluster, that is 3 x 3 of 405nm diodes knife edged, it will likely be quite satisfying. Later a 36 diode 6 x 6 will be fun.

have you seen this? I'd like to know what mirror arrays and cubes he used, but wouldn't using cubes result in low divergence than knife-edging?
.

violet is one of my favorite colors, though I haven't decided on trying to combine, with the aid of a dichroic mirror, 445 nm with ~650 to get a higher preceived brightness "violet". Or as above, to build a dedicated monochromatic 405 nm laser array either.

 

[RedCowboy]

You can only PBS cube combine 2 beams or 2 beam bundles because each is polarized, you cant use cube after cube if that's what you mean.

In that pic you can see 3 rows of 4 diodes each knife edged and stacked for a 12 beam cluster because each knife edged line of 4 beams is one row higher, you can see the 12 dots on the mirror, then a cube combines the 2 x 12 beam clusters and reflects it to a telescopic reducer. So it looks like a bigger beam but it's really a bundle of beams and can separate out to 12 spots in the far field, it's a matter of alignment and practical useful range, to go really far you need a big expander, but for medium range of a few hundred feet it could work well.

Anyway because the PBS cube is polarized you can only combine 2 beams or beam bundles as you see is done once in the pic.

 

[Project Excalibur]

Your annotation is greatly appreciated,

though I probably should have endeavored to be clearer in my original post, I was specifically asking if the use of quality cubes instead, would result in superior divergence collimation than to your suggested knife edging, the use knife edging modules that I perhaps hastily assumed would still include the still attached lens from the projector to produce the beam combining?

As far as I'm aware the resulting poor divergence that those knife-edge-lens combos produce, leaves the possibilty for cubes open as somewhat superior alternative?

 

[RedCowboy]

You do understand that you can only combine 2 beams or beam bundles with a PBS cube?

 

[Benm]

The PBS approach only allows you to combine the beams of two (knive edged sets of) laser beams indeed.

There really is no way aroud this problem with lasers of equal wavelength.

One thing you could potentially do is to knive-edge a number of lasers and then put their combined output through a prism pair resulting in a a more square than line looking pattern.

Then again once you go multimode you go closer to led's than to proper laers in my book.