NUBM44.......Share your Ideas, concepts, videos, builds and more.

Oh man I was doing some reading on Newport beam expanders and I had a great setup with those modified achromatic lenses I was using but i thought I would try a few different combinations and eventually tried with G2 defocused and was positioning the larger double lens then I noticed I had the beam to a point right on my lens and here is what happened!

I'm positive they are glass how can this happen, I had a perfect round dot the other night
Why did I try with a G2, I need to buy another now.

Wow, got a hot spot fracture.

Wow..." Some Like it Hot " hahahaha.

I swear...when I was first experimenting with the 044E....I saw something very odd... the output about 4' (1.2M) away got blurry....it looked like out of focus and blurry....as in when one see's heat rise thru the air....I shut it off defocused the G2 and did not see that again.

I think....this diode has such power density that optics can be in harm's way...Dunno....and this is especially so if ANY spec of dust parks itself....right at the focal point !!!!!

As Kent would say...." Don't ya know to check your optics Knight ???
:crackup::crackup::crackup:

Many anomalies have occurred with this LD !!!:undecided::undecided::undecided:

Later....CDBEAM=======>

Hey, to confirm using 50 percent or less of the aperture of a PCX lens reduces, or eliminates, the wings being produced by the NUBM44 MM LD, tonight I experimented with the raw output of this diode into a large 7 inch diameter PCX lens. Because the focal length of my big lens was too long to use the raw output of my diode, since the width of the beam at its 18 inch FL was overshooting the edges of the lens, I had to leave the 3 element lens in the pointer but defocused it so the beam output was about 3 inches diameter on the face of the big lens (at its focal length). When doing so, ten feet away from the lens I was able to focus the beam down to less than a quarter inch wide spot without any wings at all, this without any of the beam being cut off. This reinforces my earlier findings using half or less the diameter of a PCX lens with this high divergence multimode diode allows the beam to either be focused to a small spot, or to infinity WITHOUT wings!! No need for a Red Bull!

Due to the relative flatness of lenses with long focal lengths of 12 inches/300mm or more, I believe we would have the same result without needing to reduce the beam to 50% or less the size of the lens diameter. Perhaps 75%? Need more experimentation to know, unfortunately I don't have a selection of lenses with me to experiment more.

Edit July 6: I just received a PM the beam can be 2 inches or so wide 15 feet away when using a G2 lens, even if using 6mm as the starting diameter, which is the lens size, that would mean the divergence of the NUBM44 is close to 10 mRad with that lens, OMG is all I can say about that. If you want more burning power at a distance of 15 feet I'd use at least a 12.5mm diameter lens with twice the FL of the G2, then the beam should be exiting the lens at close to 9mm diameter and at 15 feet away the beam should be less than 1 inch wide.

Cardboard crumple about 6 inches around, 60 feet away and 15 watts of multi mode with lots of lenses to get that lovely open flame kernel and ignition.

2 of these are just using a 3 element and a 3X expander, the 3rd has a 6X pair and an expander.

How far away can you make a laser fire with cardboard or paper?

NO MATCHES

I set it on fire and then thought to get my camera, by the time I got back it was pretty well burned up, the 3 beam pic I took after the fact just to have a beam shot, the cardboard was already burned up at that point.

----edit----
To be fair the one on the right with a 6X pair in the train is doing the trick for reaching flashpoint, it will ignite at 75 feet after smoking some holes through, the left 2 with 3 elements and 3X expanders ignite nicely to about 20 feet but mostly smoke holes through at this 60 foot mark, still a ton of fun, love these expanders.