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FrozenGate by Avery

Spectro-ing the new Nichia 1.4W "462nm-470nm" NDB7675

rhd

rhd

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Just a quick thread on the spectro-ing results on the new Nichia 462nm-470nm 9mm 1.4W laser diode.

First, for good measure, a spectro reading on my DPSS 473nm so that everyone can see that the spectro is properly calibrated:

473nm DPSS - test spectro reading (here)

Now for the NDB7675... I'll first comment that what I find most interesting about these results is the degree to which the wavelength moves based on current. It's more than I expected (and was depressing when I saw the spectro results on the first test @ near threshold current).

I didn't screenshot each individual reading, but I noted them as I went. At 300 mA (which was just above threshold), this diode output a dismal, average, everyday, nothing-to-write-home-about 456 nm :p

But then it ramps up a bit... :)

0.3A - 456 nm
1.0A - 459 nm
1.5A - 461 nm
1.7A - 462 nm
1.9A - 463 nm
2.0A - 464 nm
2.1A - 465 nm

And heck, it was actually 465.53, so we should probably round it up to 466 nm :bowdown:

I wasn't willing to push it past 2.1A, and had actually planned to stop at the same 1.9A DTR did. In the back of my head, since some people have theorized that this is just a binning of their other diodes, I wonder whether it might take as much current as the other diodes too, and handle 2.3 or 2.4A. If so, it looks like the rate of increase was about 1nm per 0.1A towards the upper end of my range. If that held true to 2.4A, these could potentially hit 469 nm.

If anyone wants to setup a spectro-murder fund, I'd be happy to push this diode higher - but I would only do so if DTR still has them in stock at the time, otherwise, I'm not killing this gem unless I can replace it, and the eBay seller I got this from doesn't have them listed any more.

Nichia NDB7675 at 2.1A

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Wonderful!
Did you notice the change in color?

I'm in for a fund, as long as it's to the death (and if it doesn't die you can always keep it on at the peak power for as long as it takes) and DTR stocks them at least until the experiments are finished (cause I'll want one).
 
Atomicrox said:
Wonderful!
Did you notice the change in color?
Click to expand...

"Noticing the change" is a tough way to ask the question, because the ramp up was progressive. It's hard to "remember" exactly what a colour looked like at the beginning, if you're increasing it 1nm at a time over the span of a couple minutes.

What I VERY MUCH noticed, was the difference in colour, side by side, with a typical 9mm blue diode at 2W (I'm intentionally trying not to fall into the bad habit of referring to traditional blue multimode diodes as "445s" because that gets confusing to people who don't realize that 445 isn't usually their actual wavelength) . The difference is very pronounced. A layman with no interest in or knowledge about lasers or wavelengths would spot the difference without prompting. I suspect their response would be that the traditional 9mm diode looked "purple-ish".

Atomicrox said:
I'm in for a fund, as long as it's to the death (and if it doesn't die you can always keep it on at the peak power for as long as it takes) and DTR stocks them at least until the experiments are finished (cause I'll want one).
Click to expand...

I'm not "dying" to kill what is a pretty neat diode. I also don't have time to organize a fund. But if someone else organized, and as long as a replacement was ordered before I actually kill this guy, I'm up for it.

I agree, and would also only want to do a true traditional all-the-way-to-death fund. For one, I actually think it would be interesting to see how the wavelength progresses along the downward side of the power curve after the peak (assuming that's how the power curve behaves). If the wavelength continues to increase, and the increase is substantial, maybe there's cause for running these beyond the point we would normally consider optimal for pure-power-output purposes. I also think there is some benefit to knowing how far beyond "plateau current" these new bread of InGan diodes can survive.

Although I wouldn't make this a primary objective, I would probably try to spectro with the beam going onto an LPM, so that I could at least note some power readings along the way. But if that became impractical for some reason during testing, I would stick to wavelength only.
 
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Man, if these came in single mode variants, I'd actually want one despite my retirement from the hobby. I never really liked the diode blues due to their purple-ish hue...

Oh well, I'm sure single mode ones this high in WL will show up soon enough.
 
rhd said:
Although I wouldn't make this a primary objective, I would probably try to spectro with the beam going onto an LPM, so that I could at least note some power readings along the way. But if that became impractical for some reason during testing, I would stick to wavelength only.
Click to expand...

What I do is have the spectrometer run continuously and have the laser pointed at the LPM and the fiber with a helping hand pointing at the beam on the LPM.

Pretty easy to just up the current and check the wavelength/power then :)

I would be in for a fund to the death as well.
 
Nice job, thanks!

Do you think it's possible to a photo of the two outputs, max and min, with custom fixed white balance but automatic exposure?
 
ARG said:
What I do is have the spectrometer run continuously and have the laser pointed at the LPM and the fiber with a helping hand pointing at the beam on the LPM.

Pretty easy to just up the current and check the wavelength/power then :)

I would be in for a fund to the death as well.
Click to expand...

Is there a way to identify the wavelength without manually dragging the "identify lines" cursor to the peak on the spectrometer output? It seems like that's the frustrating part, because it has to still be done manually at each reading.

ryansoh3 said:
Nice job, thanks!

Do you think it's possible to a photo of the two outputs, max and min, with custom fixed white balance but automatic exposure?
Click to expand...

Probably - yep - though I think it should be fixed exposure as well.

And if I'm going that route, which requires using my DSLR anyway, I may as well get a shot comparing a 405/445/this diode/473 dpss/490 because the DSLR will actually pick up the differences.
 
rhd said:
Is there a way to identify the wavelength without manually dragging the "identify lines" cursor to the peak on the spectrometer output? It seems like that's the frustrating part, because it has to still be done manually at each reading.
Click to expand...

I don't think so. I just zoom in on the peak and read directly from the graph.
 
glad it came out in the middle-ish rather than the lower end. I imagine it wouldn't be uncommon to get a few diodes closer to 470nm out of a batch. hopefully these become more available.
 
rhd said:
What I VERY MUCH noticed, was the difference in colour, side by side, with a typical 9mm blue diode at 2W (I'm intentionally trying not to fall into the bad habit of referring to traditional blue multimode diodes as "445s" because that gets confusing to people who don't realize that 445 isn't usually their actual wavelength) . The difference is very pronounced. A layman with no interest in or knowledge about lasers or wavelengths would spot the difference without prompting. I suspect their response would be that the traditional 9mm diode looked "purple-ish".
Click to expand...

Cool. Now I want one more than ever :)

rhd said:
And if I'm going that route, which requires using my DSLR anyway, I may as well get a shot comparing a 405/445/this diode/473 dpss/490 because the DSLR will actually pick up the differences.
Click to expand...

Please do, that'd be amazing!
 
Nice results!

Are these still available somewhere? Or news on when the other eBay supplier will come back with more?
 
I notice he still has the disclaimer that they will be available next week lol. I feel like I should order one before they disappear.
 
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