574nm 36 mW Yellow Laser

If 976nm is actually the pump source, it will likely take a 976nm diode to pump the crystal. But, just because there is a small 976nm peak down field on one of these 575nm lasers, that is not proof that it is the pump wavelength. It will also need to be carefully aligned so that the waist of the pump wavelength is positioned properly in the crystal to get any kind of lasing, much less get a high enough efficiency to get not only a Gaussian beam, but also enough optical power out in one of the yellow transitions that we have seen here.

I'm not saying that you shouldn't try. Just don't be surprised if you don't get what you are hoping for.

For what it's worth, my phone camera can pick up the IR out from the 575 I bought from the aussie seller:


Meaning it's probably not too deep in the IR spectrum for normal phone cameras to see it.

I'd still like to know where this orange line is coming from though...

Re: Higher power fiber pumping of 575 module crystal

Paul, I understand the difficulties, I don't expect anything, I hope, at the very least, hope to see some amount of yellow, I doubt I can get it at much power without proper focus into the crystal, but I wanted to dink around and see what happens.

paul1598419 said:

I asked Jordan to post that information here, but I guess he found the other thread first. I knew these lasers weren't what he has been helping with, but the information is pertinent to this thread, none the less.

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Yea should have done this after my post run as was in somewhat a rushed state of mind but wanting to mention anothoer pump source of 885nm to make 561nm which I had not seen thrown out there in all the different combinations that had been thrown out in the other thread but yea this thread should have this info as well.

To recap.

ZRaffleticket said:

Nah the 575 is definitely IR pumped. I'll share a pic of the pink glow my camera picks up

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Oh yea was not saying those 575nm units were pumped via 450nm. I saw the forward of the diode was measured @ like 1.5V so those are IR diodes for sure. The comparison chart I was showing is from a document I was linked to showing the new very efficient method for making yellow 575nm/583nm lasers using 450nm/447nm as the pump source.

Actually I am thinking the recent drop of these units at unprecedented prices might just be those that hold large stock of either these modules or components to build them seeing which way the wind is blowing are clearing out their stock while they are still in demand.

It have heard with the high power blues over 500mW 575nm has been achieved. In the article from late last year they were using 1.5W pump and got 110mW out.

Here is the link which is behind a pay wall.
https://www.sciencedirect.com/science/article/abs/pii/S0030401816310719

overview statment of the arcitcle.
"We report an end pumped single transverse-mode (TEM 00 ) yellow laser based on Dy 3+ :ZnWO 4 crystal. The
pump light is InGaN blue laser diode at 450 nm with the maximum power of 1.5 W. A 3 cm length Dy 3+ :ZnWO 4
crystal served as the gain medium. By way of the square filter, we discuss the TEM 00 properties. In continuous-
wave operation and single transverse-mode, a maximum output power of 0.110 W and a slope efficiency of
13.0% are achieved at an emission wavelength of 575 nm."



Check out this teaser image I was given with a freshly grown crystal before it is cut into thousands of pieces with a NUBM44 shining though it..:eg:

steve001 said:

Can you provide a link to how these are constructed?

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I have this.







I also have another article here.
https://drive.google.com/file/d/1wmJr6DJYScXc0P5vPzPaRvUM4n9VZFsc/view?usp=sharing








Here is the mothership. Took a long time to grow. About a mm a day from what I am told but when it is all sliced and diced it is supposed to be able to make around 2000 of these amazing lasers.

Thanks for posting here too, Jordan. I did see the 885nm pump for the 561nm, which you think could be related to the 565nm ones we have seen recently. I am not sure at this point what crystals are being used to accomplish these two wavelengths. I'm not even sure if they are different crystals. It would be nice to see a link to the way these are made as they appear very simple when compared to other wavelengths that require much more to make them work.

I have this article, attached.

That is an interesting article from 2005, but Yb:YAB seems unlikely as the crystal used in these. They are all fiber optic coupled and etalon or birefrigent tuned to get the desired wavelength. These lasers we have are too simple to be that, IMO.

I thought ours were the same crystal, but a far less optimized design compared to the one in the article.

Who knows at this point. Someone could destroy one to find out. There are Raman spectroscopy methods and other chemical processes that could identify the rare earth doping it and the crystal's chemistry. Outside of this, I think it could be sometime before we learn for sure what it is made of exactly.

Sorry for the rushed responses yesterday. I was out and about and on my phone. I also mixed up praseodymium because of my research on InGaN pumped lasers.

Yb:YAB and Yb:SVAP is my suspicion and what I shared with Chris. They are tuneable and self doubling. They are optimumly pumped by 975nm. The pump diode has been found at 976nm by kecked. I’ve seen mentions of both 565nm and 575nm between both crystals.
It may be possible that simpler construction techniques have been found using these crystals since 2005.

To show I’m not being biased on my research. I have found discrepancies. For instance, 565nm is within doubling range of Yb:YAB but 575nm has only been seen mentioned for Yb:SVAP. According to that pdf I shared with Chris, Yb:SVAP’s doubling range is shorter than Yb:YAB and wouldn’t allow 575nm. Is it possible that both the 565 and 575 are Yb:SVAP and that the tuning range was found to be longer? :thinking:
As for efficiency, I’ll have to check later if it all tally’s up.
My only other option is that there is a new Yb doped crystal available and there simply isn’t any information available to us at this time.
It isn’t Praseodymium or Neodymium doped as the pump wavelength is wrong.

I don’t think we are going to find a definitive answer anytime soon. After ages searching through scholarly articles not a lot could be found. Even more amazing that this mysterious process has come into our hands so cheap. Regardless of what is going on inside, let’s just enjoy our 565/575’s.

Thanks, I didn't mention the source because I was probably too sensitive about someone complaining their article is on the open free for the taking net, as the site it came from normally charges for access to this article, or others like it. I cleaned it up as much as I could to remove markings from the site it was found on, but really, they had it open for anyone to google and download, as Curtis found, so probably being too cautious.

I came about it in a legitimate way so nothing wrong with sharing the source.

My concern with Yb:YAB is the necessary temp control of the crystal, the eltalon or brirefringence tuning of the crystal and mirrored crystal all seem too complex for this setup. This has been around for 13 years also, so it is not new at all. I think we might be dealing with a newer crystal here. But, until someone verifies this crystal, it is all just speculation.

That would be more interesting and now I know more, I agree.

paul1598419 said:

My concern with Yb:YAB is the necessary temp control of the crystal, the eltalon or brirefringence tuning of the crystal and mirrored crystal all seem too complex for this setup. This has been around for 13 years also, so it is not new at all. I think we might be dealing with a newer crystal here. But, until someone verifies this crystal, it is all just speculation.

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I agree, all we can do is speculate. All I've done is lay down another option to go with the others. It's just helpful that the pump diode tally's up with my findings. I suggested also that there could be a new crystal. Just it's likely (not certain) to be Yb doped.

CurtisOliver said:

My only other option is that there is a new Yb doped crystal available and there simply isn’t any information available to us at this time.
It isn’t Praseodymium or Neodymium doped as the pump wavelength is wrong.

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I had a chance to test out the 575nm at the Astronomy club last sat night.

I am impressed at how visible the Dot is at quite a long distance. Even at about 1km the Dot is very visible. It's a well collimated beam.

The beam itself it not very visible though. I did not take any Photo's as the color does not come out correct.

It will be nice if higher power ones are available at a reasonable price.