Liquid Nitrogen Cooled Oclaro 638nm Laser Diode??

[SteveT]

Impressive, that's an excellent result, have you a spectro reading on that?

 

[Atomicrox]

That's really impressive! What WL was it originally? It surely looks like it got to the 600's!

 

[styropyro]

No spectro readings yet, but it was a 638nm rated diode and it probably ended near the 600nm mark. I want to build a cell of some sort so I can get a semi-permanent solution while getting clean output.

 

[Atomicrox]

I suppose it'd be possible to build a host that can hold some LN2 for some portable orange goodness. If it's built to conduct heat poorly it might even last a few minutes each run.

 

[styropyro]

I'd be scared of the host exploding and spraying liquid nitrogen everywhere. I'm sure it could be done though, but it probably won't be a project I'll try to tackle.

I attached another picture, this one where the laser had begun warming up. One odd effect that I noticed with both LEDs and laser diodes is that their forward voltage goes way up when cooled to these temperatures.

 

[The Lightning Stalker]

Good thing there were no pumpkins around,
or they would have tried to mate with it.

But seriously, though, I think the voltage
drop is almost directly connected with the
photon energy. That is why IR diodes
always have the lowest voltage drop. I was
looking at some 1064nm diodes the other day
and I think they were rated 1.6V or
something like that. Then on the other end
of the spectrum, the near UV diodes will
drop almost 6 volts. I'm not sure why the
early 520nm diodes dropped 7V. It is
probably just a fluke with the
manufacturing process because the newer
ones are now falling right into line.

 

[paul1598419]

Did you manage to get it as far as green? The yellow looks great, but I've seen these sift all the way to green. Regardless, nice work! I love the photo.

 

[styropyro]

Good thing there were no pumpkins around,
or they would have tried to mate with it.

But seriously, though, I think the voltage
drop is almost directly connected with the
photon energy. That is why IR diodes
always have the lowest voltage drop. I was
looking at some 1064nm diodes the other day
and I think they were rated 1.6V or
something like that. Then on the other end
of the spectrum, the near UV diodes will
drop almost 6 volts. I'm not sure why the
early 520nm diodes dropped 7V. It is
probably just a fluke with the
manufacturing process because the newer
ones are now falling right into line.

I've wondered this also. There is definitely a correlation between forward voltage and emission wavelength, with higher frequency LEDs/LDs requiring higher voltages. I do not yet understand the physics behind their operation, but hope to someday!

Did you manage to get it as far as green? The yellow looks great, but I've seen these sift all the way to green. Regardless, nice work! I love the photo.

The color in the first picture is the furthest to the blue side of the spectrum that I got it. I don't think it would be possible to get one of these diodes to green though.

BTW, if we have any extra liquid helium left over during our next NMR magnet fills, I will try seeing how much further I can blueshift this laser. If the trend is linear, this diode would emit around 576nm at 4K.

 

[paul1598419]

I find it interesting that you work with an NMR. I used them when I went back to school in the 90s at CU Denver. We used them for organic chemistry in determining the composition and the chirality of organic molecules.

As far as getting it to shift farther towards blue, you might try a ML501P73-02 635nm laser diode.

 

[Hiemal]

Would it be possible to get any sort of results using TEC's?

I'm just taking a wild guess and saying that they don't get cold enough.

 

[SteveT]

Would it be possible to get any sort of results using TEC's?

I'm just taking a wild guess and saying that they don't get cold enough.

You are going to need to cool approximately 5C for every 1nm shift on these red diodes; in the typical TEC setups that I've seen the cooling capability was about 60C from 'warm state' so at very best we may see a 12nm shift in this example.

 

[paul1598419]

A TEC is incapable of getting anywhere near the low temperatures needed to get a visible a difference in the wavelength. We're talking about temperatures near the low end of the Kelvin scale. Liquid gasses like nitrogen and helium are necessary to get the laser diode down to these temperatures. Liquid neon would work, too, as it has a boiling point of approximately 27 degrees K. Though I don't know where you would get it. :beer:

 

[Pman]

Those are incredible color pics. Why oh why can't I order some liquid gases from Amazon!
I'm assuming dry ice isn't cold enough then to do much of anything. The only thing I noticed from cold from any of my units is how drastically one of my 638nm units increases in output the colder I get it. Arrived USPS back when it was really cold here in N.Y. and I took a quick test reading and was surprised at the output which then dropped quite a lot once it hit room temp hours later. I sruck it back outside for a 1/2 hour and the output jumped way up again. Should take a reading and then let it sit overnight in my -30f freezer (has a jumpered stat) and test it again.
REP for sharing this awesome experiment

 

[styropyro]

Dry ice will still have a noticeable effect...it should blue shift a 635nm laser diode to ~615nm! And thanks for the rep!

For those that are wondering...I do have a crude video made but I'm a bit hesitant to post it right now. I don't think my boss was super thrilled about me running my own experiments in his lab without getting prior approval :O

 

[SteveT]

Dry ice will still have a noticeable effect...it should blue shift a 635nm laser diode to ~615nm! And thanks for the rep!

For those that are wondering...I do have a crude video made but I'm a bit hesitant to post it right now. I don't think my boss was super thrilled about me running my own experiments in his lab without getting prior approval :O

Go on Styro post it up, what's done is done

 

[styropyro]

Alright here's a video.

I have this video as unlisted so it won't show up in search results and whatnot. I ask everyone to please not publicly share this video on the internet at the moment.

Lasers and LEDs in Liquid Nitrogen!! - YouTube

As you can tell by seeing the video, I had way too much fun doing this!!