New! Sharp Diodes 1W 520nm & 5W 455nm & +2W 638nm

[paul1598419]

Being an insulin dependent diabetic I can tell you a 31 gauge needle is plenty small enough. Love that new avatar, Chris.

 

[kecked]

Maybe you don’t glue to the diode. Maybe something fits over the diode housing with the optic in place you adjust and then glue down sealing in the inert dry gas. Wonder if you can get the can cut down close enough to do that. Let’s you adjust out rotation too. Thread it? And then glue it!

 

[Alaskan]

Will be looking into this more. BTW: Received email from Laser Tree the diodes are done and shipping now. I sure hope they are really filled with inert gas as they said they were, I’ve been lied to so much of the time by China vendors I expect lies now.

 

[RedCowboy]

Well the normal, that is without the added FAC but with a replacement window can and inert gas backfill diodes should be nice but this with FAC making a square output I just received at 1st testing appears to be no good for our " pretty beam " far field tight spot purposes, yes the raw output starts squareish but with a 3E lens the spot is as bad as ever at 5 meters as seen in my pic......It seems these FAC lens were designed for making these diodes more useful for home CNC so you get a square cutting/burning spot up close with a G2 which makes a much wider line at 5 meters, longer than without the FAC, without FAC a G2 line ay 5 meters would be 50mm but with it looks around 75mm +




3 Element @ 5 meters


DTR G2 @ 5 meters

 

[aaronnoraa]

Well the normal, that is without the added FAC but with a replacement window can and inert gas backfill diodes should be nice but this with FAC making a square output I just received at 1st testing appears to be no good for our " pretty beam " far field tight spot purposes, yes the raw output starts squareish but with a 3E lens the spot is as bad as ever at 5 meters as seen in my pic......It seems these FAC lens were designed for making these diodes more useful for home CNC so you get a square cutting/burning spot up close with a G2 which makes a much wider line at 5 meters, longer than without the FAC, without FAC a G2 line ay 5 meters would be 50mm but with it looks around 75mm +

View attachment 67587
View attachment 67588

3 Element @ 5 meters
View attachment 67590View attachment 67589

DTR G2 @ 5 meters
View attachment 67591
View attachment 67592

Well that's just craptastic...regarding the shape, I wonder if due to the correction that those diodes just need a different focal length collimating lens to achieve the correct far field geometry, do you have a G7 or G8 lens you could try? I'm thinking that, similar to a C-lens pair, that maybe the collimator just needs to be at a different distance so the correct amount of correction takes place before they collimate.

Regarding the divergence, maybe the reason the divergence is worse than without FAC is that the fast axis is corrected by reduction (rather than expansion as with a c-lens pair) and the G-2 and 3E lenses are collimating it at a point that the beam diameter is still smaller than it would be without a FAC, thereby making the divergence worse (picture it in terms of the opposite of what a beam expander achieves).

If a longer focal distance lens was used it may allow enough expansion before it's collimated due to the additional distance which would allow better than non-FAC divergence and possibly a square far-field beam. You could verify this by checking the spot size on the lens and compare it to the spot size on the non-FAC diode's output. I'll bet the spot is smaller on the FAC diode, which would then make sense why the divergence is worse.

Alternatively, this could be checked by comparing the raw output from the FAC diode to the raw output of an NUBM08 (no collimating lens). If the FAC diode divergence is better, it would make sense why divergence is worse after collimation than the non FAC diode when using a particular lens (smaller diameter beam cross section at lens output when collimated so higher divergence).

Due to the raw diode's output after FAC (I'm assuming) having a far lower divergence than the non-FAC diode, it's possible that none of the standard threaded lenses available are going to have a long enough focal distance for the raw diode output to expand enough to be optimal and that an external lens will need to be used. However, a G7 or G8 should at least quickly show if this is what is causing the problem.

 

[Alaskan]

CDBeam777 spent a lot of time yesterday characterizing the output of these diodes using 2 and 3 element lenses as well as the G8. I’m hoping to see a report from him in this thread soon.

Edit: One concern I have is whether these are really filled with inert gas and if so, how good the can seals to keep it in.

 

[RedCowboy]

This is the nubm08 with FAC and the raw output makes a great big square in my backyard, it seems to stay reasonably square as it diverges but with any of our common lens 3E, G2, G8 it focuses to a long line just like you would get without the FAC only about 50% wider.

I am confused as to why it's not focusing to a square, but what I don't know about optics can fill many books.

 

[kecked]

Wonder if addition cylinder lens might bring it back? Likely end up with giant square at distance. I was thinking to use the installed fiber as half the cyl pair. Looks like the correct the fast axis instead of the slow axis. I had hoped they where matching the two together so the slow axis diverged same as the fast axis.

 

[absolute]

Darnit, I had high hopes for these FAC diodes to be an easy fix for the crappy multimode divergence..
Thanks for buying, testing and reporting about them on the forum though, much appreciated

 

[logsquared]

Put a 30-80mm FL spherical lens in front of it. Problem solved.

 

[Alaskan]

He's working on a solution to use a smaller diameter lens we are constrained to use for a project, but if it wasn't for the need to use a 6.3 mm diameter lens, I'd be happy with a larger lens as I love the lower divergence of a fat beam

 

[RedCowboy]

I used a 25mm bi convex lens and was able to focus to a tight spot/line @ 2 meters from about 75mm out but the beam ran from about 15-17mm wide to the point, not the beautiful beam we like for lightshows ect...also the beam strikes the lens square but focuses down unevenly becoming ( ribbon like ) and ending as a small line/spot

 

[logsquared]

I used a 25mm bi convex lens and was able to focus to a tight spot/line @ 2 meters from about 75mm out but the beam ran from about 15-17mm wide to the point, not the beautiful beam we like for lightshows ect...also the beam strikes the lens square but focuses down unevenly becoming ( ribbon like ) and ending as a small line/spot

Hmmm. Well its never gonna be square because the ratios of emitter size to divergence of the raw diode are too "uneven". But if you can't get a better beam/spot than an un-fac'd diode my guess is the FAC is making the astigmatism worse. Two cylinders, one for X an one for Y should fix it.

 

[Lifetime17]

Hi,
I know this won't solve the divergence issue. But if no one can figure it out with this FAC diode make a really bright flashlight out of it.
Rich

 

[Alaskan]

logsquared: Hmmm. Well its never gonna be square because the ratios of emitter size to divergence of the raw diode are too "uneven". But if you can't get a better beam/spot than an un-fac'd diode my guess is the FAC is making the astigmatism worse. Two cylinders, one for X an one for Y should fix it.

Am I to then assume FAC lenses are primarily used to square up the beam to allow it to be focused to a more uniform spot for burning and not for beam correction use with pointers?

 

[logsquared]

Am I to then assume FAC lenses are primarily used to square up the beam to allow it to be focused to a more uniform spot for burning and not for beam correction use with pointers?

Its not going to work with the standard lens we are used to.

The FAC does give us more leverage to get a "squarer" beam. It should be simple as a longer FL colimation lens. RC didn't have luck with a 25mm bi-convex. Not sure why, should have produced a "squarer" beam than the same un-FAC'd diode with say a 3E lens. I would try a 40-50mm plano convex next and see what happens.

As Kecked pointed out you could also use a standard lens, say a G2, then correct the fast axis with just a plano convex cylinder lens. (this is opposite the axis we normally correct with a cylinder pair). I would start with a 50mm FL cyl. first. This will actually make the beam more square but less bright too. The bar shape will grow into a box shape. So a BE will be needed to reduce the overall divergence.

Another thing to think about, the FAC'd greens should do better than the blues and reds becuase the greens have a better raw aspect ratio.

I am sure CD beam won't stop until he hammers the best beam out of the samples he has.

My biggest concern would how much power is lost on the FAC and the quality of the beam leaving the FAC. We don't have any control over that part. The collimation I think we can collectively handle.