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FrozenGate by Avery

DIY - Pink / Magenta - TEC Cooled Labby

rhd

rhd

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Thought I'd post some quick pics of yesterday's project. Recycling the old casing of a strange dual pump DPSS 532 labby that I got essentially free, I decided to create a pink/magenta (445+660) labby.

This is a total low-budget build. The PBS came out of the recycled DPSS labby, as did the TEC for the ICs. I'm using those cheap $3 aixiz mounts, and a TEC cooler from a KasEO projector for each diode. The unit is driven by triple-1084 LDO ICs, and will require an external power supply of roughly 8V / 3A. Works well off decent 18650s for now. Adjustment was a PITA, and required a lot of patience while epoxy dried. I also killed the 445 in the process of testing this morning, so technically this beauty is dead until I pop a new 445 in. The lesson, don't run this guy without its TECs on for very long ;)

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Beeauuttiffulll!!! =) Very cool idea, wouldn't mind seeing some more pics. Looks like the 1 laser is emitting the magenta, I don't see a blue or red beam coming from it. Is that just reflection?
 
Last edited:
random person said:
Beeauuttiffulll!!! =) Very cool idea, wouldn't mind seeing some more pics. Looks like the 1 laser is emitting the magenta, I don't see a blue or red beam coming from it. Is that just reflection?
Click to expand...

Yes - some of the 445 is bouncing back into the 660.

It's very odd, the PBS is VERY inefficient. It's taking 1,500mW of 445 to balance ~250mW of 660, which makes no sense whatsoever. The 445 seems to split 50/50 (forward and right angle) through the cube, when rotated appropriately.

My sense is that either 445s aren't quite as uniformly polarized (this doesn't make sense to me though), or the PBS just doesn't work well for 445. This PBS is over 20 years old, and was made for IR - not sure if that matters.

I may try swapping the 445 out for a 405 - simple to see whether having single mode is a benefit.

Nice bonus though, I didn't actually kill the 445 - it just stopped working because the IC overheated (again, this thing can't be run for long stretches of time without the TECs on.
 
Very nice looking!
Thanks for sharing so far. I would be interested in more detail about the driver and, more so, the TEC controller(or such).
I'm still working on my 674nm TO-3 with TEC, trying to balance the output.

BTW...the second pick is a sweet beam pick!!:beer::beer:
 
The poor PBS efficiency is probably because it's ment for 808nm. 660nm is still somewhat close enough to work, but I'm not surprised it doesn't split properly at 445nm.
But even if it splitted 50/50, would there be 750mW of 445nm needed make magenta with 250mW of 660nm? I'd think 400mW of 445nm would be enough. Isn't the cube splitting the other way around?
btw you still have the parts of the green laser that once was?
 
I've actually heard a few cases where there are huge inefficiencies with 445 and PBS cubes. Theres a thread on PL about it somewhere.
 
Bluefan said:
The poor PBS efficiency is probably because it's ment for 808nm. 660nm is still somewhat close enough to work, but I'm not surprised it doesn't split properly at 445nm.
But even if it splitted 50/50, would there be 750mW of 445nm needed make magenta with 250mW of 660nm? I'd think 400mW of 445nm would be enough. Isn't the cube splitting the other way around?
btw you still have the parts of the green laser that once was?
Click to expand...

I think the inefficiency could actually be worse than that.

And yep, I still have all of the parts :)
 
rhd, I know you have some projectors laying around and you know that one of the dichros in it will pass blue and reflect red? You would get much better losses if you use that instead of be pbs. You will loose about 9% of 445 and around 4% of red.
 
I think I need to grab some proper dichro mounts from modwerx.
 
Dave on PL has some good ones. You bend them into place so its never need realigning. I believe they are $15
 
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