NUBM44 6W+ 450nm Laser Diode

I'm doing something different with my photo's, the beam is focused to as sharp a point as I can get, instead of infinity focus as you are doing. I need to adjust to infinity and make a close and far measurement next to get the divergence figure for it.

I want to find about a 5X expander, I would use podo's 3X but it is tuned to his G7 lens and that's like a 3 element... you know I may just try it.

I'm not able to find expanders coated for the blue wavelength, green and red yes, blue no. You can make your own without AR coating, that's what I'm having to do.

Here's a photo showing how tiny the beam waist is when I focus the beam to a point about six feet away, that is as close as I can adjust the expander to focus at. The photo doesn't do justice to show it, but the diameter is probably 1mm or even less by the looks of it to me. Tell me you can get the beam to focus that small using your little 6mm dia. lenses that far away, not! At the focal point of the waist, the beam is so small it looks perfectly round, much like a skinny needle, no correction needed for burning.

I can't get over how large your lasers are Alaskan. I think we need a new category such as "bi-hand" or something. You need a clip on each end for a carry strap
By the way, I think you asked me a couple months ago if I had built any single modes. Besides for already building a bunch of bdr 405nm I just picked up all the more powerful single mode diodes DTR sells last week and am working on the builds. What I mean by more powerful is instead of a 120mW 638nm I chose a 180mW 638nm.
Build on. Burn on (for RedCowboy).

I don't have any waste with the unfocused G2 I used with a large PCX lens as the collimator, none. Whether the beam gets cut off some or not depends on how far away the collimation lens is, if it is four inches away, you don't need to de-focus the G2 very much and because of this none of the light is lost.

At 60 feet, the smallest point I can focus to is a 2mm X 12mm line, at 30 feet 6mm wide line but it burns into plastic more like a round spot, as shown in my photo.

You have had some good results, it's not simple and takes a lot of adjustment but if it works it works.

If you reign in the highly divergent axis via correction, you can use your expander and get even better results and with just one adjustment for focal point at range.

If you correct your beam, and use that big expander, you should get some really hot focal points.

Yea you are falling off the edge of your lens somewhere on that garbage can shot, you should burn a hole through that can pretty fast with a nubm44 focused into a spot that size, you must be clipping at least some just by the shape.

I tried to limit the time the beam was on the can, I was afraid it would burn through it, and even though I only had the beam on for a very short time, it almost burned through.

If it works it works, and it looks good too.
One build I am going to do is about the size of 2 packs of cigarettes end to end, maybe a little shorter.

Batteries down one side and my nubm44 and optics down the other with a trick hidden pair of switches, a rectangle box build with a lens flare hider built in. Just a little pocket blaster.

Like this one only a little longer, all polished aluminum plate.

I just measured the power out of the G2 lens focused to infinity to be 7 watts and then defocused enough to expand the beam to two and a half inches wide and the power reads the same, so this tells me the amount I am adjusting the G2 lens of out of focus isn't enough to cause the beam to be clipped.

Sounds like good solid science too me. :beer:
What do you get focused to a point at 4 to 5 meters?

Can you put a drawing up showing the beast you plan on making using this diode?

I would like to do a 3 nubm44 trident, but heatsinking will have to include some fins to keep a decent duty cycle, just making it massive is not enough, fins work.
I would love to do a 6 or 8 diode cannon with corrected 44's and galvos, but I will need to harvest my own diodes and build drivers to justify spending the money.

6 corrected 44's one each at one end of a 2.5 to 3 inch wide 36 inch long 1/4 inch thick aluminum slats with a mirrored galvo at the other end on an elevation block controlled by a raspberry or generic processor and employing a rangefinder to converge 6 beams at the ranged distance, up/down left/right adjustments for run out at the galvo end and laser end, as well as tilt angle on the laser end, alignment must be adjustable for run out.


Good quality galvos would be accurate enough to converge 6 or 8 corrected beams out to 50 feet, the cannon would need the size and surface area to dissipate the heat and have a good duty cycle.


The reason to elevate the galvo/mirror is so it wont hit the laser housing on longer distance convergences. 8 would be better and allow more headroom. Along with being fun this would look really cool with the larger user end spacing, 8 beams from a device about 6-7 inches in diameter would look epic all running out to a cluster point.

Also the longer the slats the more accurate the galvo can be as the ratio of the final distance divided by the length of the slat will be better for a 36 inch slat vs a 18 inch slat.

I could make the slats 3.25 wide and just use 5 corrected 44's, this gets expensive, but it would look so cool.
I have metal blades and table saws so I could rip down the slats with mitered angles for a clean fit.

I will probably just do another heavy single so I can wield one in each hand, then a cubed double and my compact. But a small telescopic reduction set on front of a corrected 44, built into the housing could be lots of fun.
Also just a cubed corrected pair of 44.s would be pretty fun, maybe with a telescopic reduction set.
It's too bad they are not 520nm 7 watt diodes huh?

Afterthought, heat is a much bigger factor than most people would think, my triple 7875 gets hot in 150 seconds, and that's 2.4A a 5V each in , so 12 in 3 out 27 watts of diode heat then the driver heat...it gets hot.
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SO what do you want to build next? :lasergun:
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Looking at you guys pics has me cracking up, reminds me of myself burning crap around the house. My wife is always finding little marks and she proceeds to "confiscate my lasers". The latest was a burn mark on a ceiling fan blade, I was just giving it some character! Pro Tip, don't ever be dumb enough to let a focused beam accidentally cross your laptop display! Even a fast swipe with these diodes will destroy every pixel in its wake.

Anyway, these DIY beam expanders are really interesting. With mine that I made years ago I was amazed at the difference it made with divergence, but then again it was a 532nm, they have a great beam to begin with.

With the poor beam characteristics of these multimode diodes, this seems by far the easiest was to get a decent beam in a portable laser. Prisms would make it unportable, fast axis correction is hard to do for a DIY.

Thanks for the ideas! I'd rep ya if I had any points:cryyy:

RedCowboy said:

Sounds like good solid science too me. :beer:
What do you get focused to a point at 4 to 5 meters?

Click to expand...

Double post sorry! Your video reminded me of something that happened recently. I was in my front yard with my NUB44 445 that I built. I was focusing it at a tree and then pointed it into the sky. I'm responsible with my lasers and would never point it at anything living or at an aircraft, etc., idiots that do that deserve jail time. Anyway, the road at my house is close like yours, and out of nowhere a sheriff car pulls up and the Sherrif gets out, I figured oh shit here we go, I'm going to jail for something stupid. I showed him the laser and explained how I built it, its a hobby, im basically a electronics/tech nerd with no bad intentions and that I'm very responsible with it, my wife came out gave me the evil eye and thankfully backed me up(she hates the laser hobby). He said that when I shined it into the sky, he could see the beam from two miles away! That night the sky was clear with low humidity so the beam doesn't show up like it does on "good nights". The cop didn't want to arrest me, he wanted me to build him one after he saw how awesome it is. I did just that and he loves it!

Cool deal.
Yes the beam looks much brighter coming toward you than going away, I am a big fan of lens flare hiders, just to avoid misunderstandings.