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200mW 375nm UV Build

ZRaffleticket

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Hi everyone. I got my hands on a couple new toys... some 375nm UV laser diodes.




First and foremost... don't expect these to suddenly start flowing in like the sharp diodes did. This find was lucky; and that's all there is to it. I'm on a couple mailing lists for diodes - every now and then something strange pops up - this is one of those cases, just like with the 480's and 495's a few years ago. I don't think these are going to be in constant supply, especially at a reasonable price. These aren't the most expensive diodes I've ever bought, but they're not very far from it. I imagine at least one of the other buyers involved will be showing theirs off, so I'd like to make this post to claim the record for the most powerful UV handheld laser, even if only for a few days :cool:

All that said, let's get on with it. For my build, I asked Rich for this:
Got anything like aluminum with a plain brush finish? I want something kind of dull looking but also screams "this is dangerous". I'd prefer a host without a momentary button.
A few days later I had this waiting at my door. He nailed it.


On the inside, I settled on a micro flex drive and a G8 lens. The datasheet suggests 370mA operating current, so I soldered the micro flex to the 100-412mA range, and cranked up the pot. After that, the most stressful part of the whole job. Pressing the diode, soldering it to the driver, and making sure it all works. Thankfully it went without any problems and I didn't ruin a diode that costs more than my first car.


Finally built, and what can I say..? The color is not what I expected it to be, having a 355nm to compare to. I expected this to be a dim blue-ish gray, but it was actually a dim violet. If you pointed it at a wall and called it a true 5mW 405nm, I would believe you until I saw the rest of the room glowing.





Something that will be a lot of fun is seeing what all glows in the dark. My ceiling tiles do.


The diode is multimode, and I'm able to compare the spot sizes with some cyanotype paper. (30 feet and at aperture)


Classic bar shape. That said, it being multimode is usually unnoticeable, it's way too blurry to tell after a certain distance. If you're familiar with the halo around a 405nm, imagine the same thing but with about 3 times the diameter. But... get too far away from it, and the halo surrounds the spot fluorescing whatever material it's pointed at. Really, really odd to look at.

Anyway, that's a wrap. Full album of pictures is here, every now and again I add to them here. With this being fairly dim, it admittedly probably won't see much happen.

---

Adding some testing notes... Good reference material for anyone else who may locate these.
Driver - Micro Flex Drive (380mA)

LPM is in the mail; ETA 1/25. Stay tuned.

LensPower OutputSize (33 feet)Notes
AcrylicN/AN/ALens melted.
3 ElementTBD3/4 InchesMarginal loss in power, evident in brightness. Surprisingly not the best beam shape either.
G2TBD1 1/4 InchesHighest output power, evident in brightness. As expected, worst beam shape.
G3TBD5/8 InchesTo my surprise, seems ever so slightly better than the G8. Coating? LPM will tell.
G8TBD5/8 InchesPretty good. Far focal length, not my preference for making handhelds look nice.

 
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CurtisOliver

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Very nice Zraffleticket!
Based on your description I can get a very good feel of what a 375nm laser is like. The halo and blurring, and the dim violet. All things I expected at this part of the spectrum. 375nm is the same wavelength that most common uv torches come in. So can also get a feel for the brightness of the fluorescence compared to the emission.
A very unique laser in your collection and nice build. Well done.
 

RA_pierce

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Very cool. I've been looking out for these diodes for a few years and have never seen one show up anywhere before.
You're lucky and I'm jealous! I use an LED light of ~365 nm for fluorescence photography (see my profile picture) and always wanted a laser in the UVA range!
That's ok. I have something pretty special headed my way as well...
 

gazer101

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Beautiful! Once I can afford it I'd love to make an epitaxy and lithography lab so that I can produce these and other exotic wavelength lasing crystals

Won't ever be profitable of course, but its still a shame that nobody makes them
 

blueasthesky

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Very nice build Z. Is 355 nm harmful enough that you would limit your exposure to this laser? (i.e being in an enclosed room with this or simply a small confined area) :)

Thanks!

-Alex
 

ZRaffleticket

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Thanks everyone!

Yeah this diode is usually prohibitively expensive, I got it for a fraction of the price you saw but it's a couple times more expensive than anything DTR sells.

My 355nm is much less powerful than this, sitting around 11mW. I avoid using it more because it's louder than all of my other lasers combined - including the argon - over it being a hazard because its UV. Tanning booths are way worse, and direct sunlight is probably more exposure to 355nm than a couple minutes in a room with this scattering off the wall. Then there's this 375nm diode sitting at 200mW which scares me way more because it's so dim but it's many times more powerful. Not really scared of either because "UV = bad", it's much more that it's hard to see and easy to make a mistake with these just like it is with IR.
 

Phillip

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Hello!
Just if someone is interested, I can offer some of these diodes for 300€!
BR
Phillip
 

ZRaffleticket

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That would be even cheaper than I got them for, though kind of the same ballpark. Some warning on them, operating temp is 20-30C (68-86F). Gotta keep runtime short.
 

Phillip

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A lot of people know me here... and on other forums.
I´m btw. the owner of LIVE Lasersystems.
 

CurtisOliver

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Don't take it personally Phillip. I can sense where he is coming from. There are many members on here I would trust however.
Maybe he could reach out to you directly at your company so you are not some stranger on a forum.
 




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