My DIY Greenie Pointer. 50mW@25% efficiency

[JLSE]

Here is another with the crystals exposed only to the open can diode. No fast axiz lenses.

 

[diachi]

thats really good, well done :, cant wait to see those outdoor shots :

 

[IgorT]

Great work Wannaburn!

I'm planning something similiar, with a 0.5W diode and CNI crystals in a body with a huge heatsink. Unfortunately i have so much work at the moment it'll have to wait almost till the end of may...

Where did you get that diode BTW? I was hoping to do mine with a C-mount with built in FAC but it arrived totally demolished (the laser die with the micro lens hanging on the negative wire, separated from the base), so now it's gonna have to be a DX 0.5W diode.

If i get stuck, i hope you'll share some tips. I already managed to get 79mW with cheap crystals this way, so i really hope the CNI crystals will do a better job. I was hoping for 150mW, but that is VERY optimistic without FAC. :


Oh, and which IR goggles are you using?

EDIT: The pump holder is from one of those lasers with a separate PD on a 45° angled reflector, right?

 

[JimJo]

thats really good, well done :, cant wait to see those outdoor shots :

Whats with you and your rolling eyes? Its annoying

 

[usakicksass]

I was wondering, is there a axial alignment(of the crystals) that is very critical. Also is the distance between the components critical.

 

[IgorT]

For max output, the diagonal of the crystals has to be aligned with the fast axis of the pump (unless you use FAC), and the distance of the crystals matters a lot, because the IR is uncollimated and spreads. Both are critical, because you want to get as much IR in as possible. The tiniest difference in the angle or the distance can completely ruin the output.

If the IR was in a thin straight beam, both the distance and the rotation of the crystals wouldn't matter nearly as much, but the crystals would have to be able to withstand a much higher power. That's why cheap lasers don't use any IR collimation.


Aligning the crystals with an uncollimated IR beam is a slow and painful proces and the sweet spot is much harder to find..

 

[JLSE]

I have tried this in different ways. First try (not this project) I used the FAC assembly in a DX true 30, and couldnt get passed 50mW. I then spoke to an ebay seller who builds greens, and his words of advise was to scratch the use of additional optics. The only time FAC should be used is when dealing with a diode that is not open can. Using an open can allows the crystal closer proximity. So when mounting mine, I removed the can from the diode and snugged the crystal as close as possible. In this build the yvo4 protrudes from its heatsink by a fraction of a mm, almost touching the emmiter on the diode. Even with multimode 1watt pumps, this method seems to be the better route, and squeezes the extra power. For adjustment I tacked the crystal in place with a small amount of adhesive, made the adjustments and then bonded it permenently. From my experiance, the closer you get it the more power you get out. Heat doesnt seem to be an issue either. On the larger builds I use a heatsink for the crystal which can adjust the postion and screws and a plate to fasten it. The next step is to ensure that there is no mode switching issues when it warms up. In my larger assembly with a (measured 480mW) 808 pump, im getting over 100mW out, again this is an open can with no FAC. The goggle im using are good for 808nm only, but am not seeing any 1064 passing through them on a 0LUX sony cam.

 

[IgorT]

Does the DX true 30 really use a FAC lens or is it just a normal collimator? I haven't seen it yet. I've had no luck using optics between the pump and the crystals either, but i was hoping the c-mount with a microlens would do better.

Otherwise, i had the same results with the 9mm open can. The crystals almost had to touch the diode. Unfortunately, you can scratch them or ruin the diode if you're not careful, this way..

Did you also have to use the diagonal alignment for the most power? I usually use a collimator as a "microscope" to look through the crystals and see the chip on the diode and align it, before powering it on and doing the fine tuning.

 

[JLSE]

With the true 30, when the diode is removed there are two small lenses stacked on top, in between it and the crystals. When I  tested these lenses by shining a fine green beam through them I noticed they were of poor quality. They separately produced a large dot on the wall with more imperfections than a dollar store pointer acrylic lens. I will eventually try this configuration with better optics and see if it improves the total output.

 

[Benm]

Looks like excellent work!

One question though: are you using the crystals from a DX20 or did you replace them for new crystals?

 

[hutch123]

Very impressive! A true Jedi you have become!

Nice pictures and explanations throughout - thanks for taking the time to share!

 

[JLSE]

Looks like excellent work!

One question though: are you using the crystals from a DX20 or did you replace them for new crystals?

On this build I used "better" crystals, but they are still cheaper than the ones I have put aside for my Rominsen hax. While the heatsinking is good, I didnt want to run into mode issues and used the cheaper ones for this. The ones ill be putting into the Rominsen 30 body will be blessed with the larger heatsink, and .6v more.

http://www.laserpointerforums.com/forums/YaBB.pl?num=1209451614

 

[pwnstar]

I tryed re adjusting the crystal on my DX200 and failed. But the way you did that, you make it look so easy! lol, How long did it take you to adjust the crystal?
This kind of makes me want to try to fix the DX200 again...

 

[JLSE]

It took about 25mins, turning and positioning. I could have went a little further, but was anxious to get it together. My findings have been to get the crystal set as close as possible to the diode, and go from there. I practiced with the cheap parts on DX greenies for about two months. You eventually get the feel for it. I figured its like anything, dont start with the best rather make the best of the worst. There is much more to learn that way, and any mistakes won't empty your pocket!  

 

[Benm]

Startin with cheap parts is probably a good idea. I managed to re-mount a dislodged crystal set into a kaidomain 50 mW CR2 laser, which works reasonably well.

I have another KD50 with shot crystals, and a DX20 that suffers from pretty bad dimming issues most of the time. I'm considering transplanting the crystals since both lasers are pretty useless to me as they are now, and i think its worth trying just for the experiment.

 

[JLSE]

Sounds like a fun project If you dont have 808 protection, you may want to get that first. If your dealing with a 200mW pump they most certainly are a must.