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[Unown (WILD)]

Man wish I had money -_-

 

[Alaskan]

The seller I bought the 1.5 watt diodes from is out of stock for about two months, they are reording more but it may be that long until they get them. You can however find them on Aliexpress for both the gball and the capped version, but more expensive and without a FAC lens.

Edit: Working with this FAC corrected diode, the collimated beam is far too thin producing large divergence. A fix for this might be adding a 6 mm double concave lens with a short negative focal length inside the lens barrel to first increase the beam diameter, then collimate the beam with a long focal length lens. After expansion, even if collimating using a standard 6.3 mm diameter lens with a 8 mm focal length to do so, it should increase the beam diameter several fold without overshoot, at the right focal length.

 

[Alaskan]

Sneak peek, full post with beamshots later in the green section:

Works! 3 watts 525 nm out the end using two FAC NUGM04 laser diodes. In the first photo the two diode mounts are just sitting on thermal grease and not fixed yet, due to wire tension the upper one slid forward out of place while taking the photo, to be epoxy fixed into place later. They need to have the same distances of travel to the PBS cube. I did test it at full power, more photo's later.



Above photo, left optic on brass mount is a half wave rotator or waveplate to turn the beam of one diode 90 degrees so the pattern from each diode (which are entering the cube at a 180 deg. cross polarity) exactly fall upon the the other in the same shape. To the right of the waveplate is a 10 mm PBS cube to combine both polarities into one beam. The other diode simply has a turning and positioning mirror so both beams sent into the cube align coaxially at the output. Two BlackBuck8M drivers.




Most of this host was built by @trinh hong phuoc who did a great job designing everything you see but I removed the two diode mounts he made for it because I had a problem with the threads tapped into the soft copper (I asked for) and hard steel set screw which I twisted too much, ruining the threads in the copper. I could have retapped it for a larger diameter screw, but wanted to try these lasertack.com precision no-press diode mounts and they worked great without the need for a set screw. This host also came with a brass runway mount for a pair of 6X cylinder lenses (originally for a couple NUBM44 diodes) but with these FAC corrected diodes, I didn't need them.

How it works: Using a PBS cube, the polarities of each diode must be 180 degrees apart, otherwise the power from each diode will be reduced through the polarized beam splitter cube (a necessary problem if wanting to coaxially combine two beams of the same wavelength). However, with the two rectange shaped beams from each diode entering the cube 180 degrees different this produces the shape of a plus sign; +. To align the beams on top of one another in the same shape, a half wave rotator or waveplate is inserted in the path of one diode. The product of this arrangement is the beam shapes are then identical and when properly aligned both exit the cube at the same spot in such close alignment the output appears to be a single beam but at the combined power of two diodes, minus some losses.

This is my first PBS project, the setup worked and produces a full three watts of output power.

Parts:

2 each 525 nm 1.5+ watt output FAC diodes from a NUGM04 block: https://www.ebay.com/str/lasertree (out of stock now).

2 each precision diode mounts from www.lasertack.com

2 each BlackBuck8M drivers from ebay seller barnett_unlimited and DTR LPF at https://sites.google.com/site/dtrlpf

1 each 1/2 waveplate, 515 nm from ebay seller mi-lasers; http://vi.raptor.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=202736829428 (515 close enough to diode WL).

1 each 10 mm square mirror from ebay seller 3dphotonics

1 each green wavelength PBS cube from https://optlasers.com/polarization-beamsplitters/pbs-green?search_query=pbs&results=3

16 gauge silicone wire from ebay seller kuajie2017 (much larger than needed, but I prefer that to minimize voltage drop).

I listed both sellers I've bought these drivers from because I don't know where they came from now, I have ordered these from both sellers, both are great.

 

[Alaskan]

Swapped back to the original diode mounts due to better heat sinking



Just over three watts of 525 nm green, but for some reason I cannot parallel the power supply or battery input into both BlackBuck8M drivers together, when I do, it will only put out 2 watts when both drivers pulling current off the same source. I have confirmed the problem is not due to voltage drop and the power supply is capable of multiples of the current they draw together. There is something interacting between the two drivers, when I power both of them off of separate supplies, then no problem, full output.

Has anyone seen this before with driving two diodes like that?

 

[Unown (WILD)]

How much voltage is your psu outputting? Maybe the drivers were designed to share an average output to run in parallel with each other if they detected a certain voltage or current drop

 

[Alaskan]

8.2 VDC, the diodes only need 4-5 VDC, the supply is capable of 30 amps, drawing less than 5 amps total. Very short 16 gauge wires, just a few inches to the power supply. It is behaving weird, if I hook up each diode alone, not powering the other, then full output, hook the power to the drivers up together and reduced power. It is acting like there is a current or voltage drop problem, but that isn't occurring.

 

[Lifetime17]

I ordered ten for a project, need eight, two are spares. The package looks full, but it is only the bottom row. You can however reach out to the ebay seller and buy a single unit from them, I will PM you.

I just finished powering up this diode, the power is awesome, I will measure the power later when I get home, put this together during lunch at work, already had everything ready to pop the module in. Power out of a Techhood G8 lens (disappointed, is not 8 mm FL, closer to 5) is 1.6 watts when set to 2388 mA, so the 1.5 watt spec at 2.3 amps is probably what it does at that current. I didn't run the current through ranges yet, just set it there doing a power-on to measure current and then power off to do the adjustment each time, no way to know where it really ends up with much accuracy each time that way, but small movements so I didn't go too far. Will do so later.

Edit: Updates below.

Having arrived home and made a power measurement and trying to adjust the output higher, it appears 1.6 watts is about what to expect for max collimated output. So unless I am having a driver issue, I can't get much more out of this first diode. For a diode designed for 1.35 watts at 1.9 amps, 1.6 watts isn't too bad. My plan was to only use them up to 1.5 watts output at the max rated current of 2.3 amps.

Below, photo after power being readjusted, didn't adjust high enough to hit 1.6, but close enough. Only surprise is the divergence is shyt, about 9.13 mRad in one, 4.35 mRad in the other polarity, far worse than a NDG7475. While I am sure the FAC lens added helps a lot, that still isn't a square beam, not at 15 feet and certainly not at 100 feet. Uncollimated the beam appears square, but for some reason not when collimated, in addition to the FAC it needs 2 x expansion and a 5x beam expander minimum, IMHO. I tried it with a 10X expander tonight and then the beam then looks great, even without a 2x cylinder pair it is a nice narrow far reaching beam.

Although the beam characteristics are disappointing, even with a FAC installed, the power is not. For my application the wider divergence of both polarities won't matter, I intend on using a beam expander on it, had from the start before I found this. Wish for higher power green diodes? You can, for a price; higher divergence.

My thought is with this kind of power from one diode, wouldn't it be cool to make a pointer using two of these diodes through a PBS cube, cylinder pairs to correct the beam shape more and a 10X expander, then you would have something awesome.


Brass and copper 2x 26650 battery host by LPF member Rich Lifetime17



Re: Above photo, see that slightly larger appearing squared off tip at the end? That is because the divergence is too high (for what I like, being this is a toy without an application beyond fun, there is really no such thing as too high). Because of how far away it is, for what I want to see the beam should look more narrow at the tip, not flat, but is expanding far too fast to give that appearance. The tip is a big 2 x 1 rectangle at the end and at that distance is huge up there..

Hi Alaskan,
Crap just seen this thread , I forgot all about that host. I guess when you make so many cant remember them all.
Looking good with that big green beam. I am working on a 2X26650 host with a 1-58 diameter copper heat sink . Will be bored out for a DTR 25mm copper module with driver shelf. AL battery tube and tailcap with powder coating. Just need some time for me .
Customer come first.
Rich

 

[Giannis_TDM]

8.2 VDC, the diodes only need 4-5 VDC, the supply is capable of 30 amps, drawing less than 5 amps total. Very short 16 gauge wires, just a few inches to the power supply. It is behaving weird, if I hook up each diode alone, not powering the other, then full output, hook the power to the drivers up together and reduced power. It is acting like there is a current or voltage drop problem, but that isn't occurring.

Sounds like feedback loop interference between the 2 effectively cutting their current limit in half. Adding an Isolated DC-DC converter in series with either of em should solve the issue.

 

[Giannis_TDM]

How much voltage is your psu outputting? Maybe the drivers were designed to share an average output to run in parallel with each other if they detected a certain voltage or current drop

No driver IC available to us is advanced enough by itself to do that.

 

[Alaskan]

Rich, I might want the host Yea, had more than one of these made but just recently started working on getting one going.

I ran the drivers off of separate 8.2 VDC power last night and then no problem. Full output,

I’d rather change the drivers to the SXD V3 instead of the BB8M, if I have to isolate them with another board, but they might do the same thing!

I emailed Wosse today asking if he has heard of these drivers interacting before.

 

[Lifetime17]

Hi, Alaskan,
Im starting to work on the 2x26650 host in the morning, im still debating to coat or not to coat the host
Rich
Well so much for the 2X26650 , I decided to go with 2X18650's .

 

[Alaskan]

Looking forward to see what you chose to do. I have the driver issue worked out, with the 4 mm hole in the DTR solid back ends of his 12 mm module, difficult to run 16 gauge wires without one of the pins with solder on them touching the copper, both cathode lines were touching the copper, the driver outputs need the cathodes isolated from one another. If I had my druthers for these modules, I would have made the hole a bit larger, 5 mm would be better but then he would need to adjust the inner ring which pushes against the back side of the diode and not sure how that would affect the total design.

Next time I will just drill out the hole bigger.

 

[Lifetime17]

Hi Alaskan,
PM sent,,,.

C17C349B-F246-4CF9-88C8-C11BE2D54503.jpeg

• Lifetime17
• Jan 3, 2021

 

[paul1598419]

That is a nice looking host, Rich. Is it all copper? Can't really tell by just the photo as it could be brass. I love it though.

 

[Alaskan]

Rich, PM sent on the host, sweet. Is that a brass handle?

 

[Lifetime17]

Rich, PM sent on the host, sweet. Is that a brass handle?

Hi.
Yes Brass handle /copper sink, I knurled the heat sink fins.
Weighs in at 2.159 LBS. the heat sink is 1-5/8 dia. and 11 in long, battery tube is 1-1/4 dia.
Rich