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Request for NUBM44-V2 Spectral Data

CurtisOliver

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Hi all,
Just putting in a request for any spectral data anyone has on the NUBM44-V2.
I need to know what wavelength the diode is at their chosen current setting.
I would need the voltage, current and output power to go alongside, as I am trying to determine whether they are possible to cool down to <445nm and how the current affects the central wavelength.
Thanks,
Curtis
 



paul1598419

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I would love to help you, but my laptop that i use for my spectrometer fell and no longer works until I can get it apart and see what damage was done to it. Sorry Curtis. :(
 

lasingfox

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the one i tested was rather low but i'm not sure if mine was just defective. I picked up a cheap sanwu striker and it started out around 435nm and settled ~440nm doing the full 7.5w. this is the only nubm44-v2 i've had and tested so i'm not sure if this is standard. color looks identically to 445-450nm though so don't get your hopes up for a nice indigo color. everything from 430-450nm looks more or less identical to the human eye in my experience. 422-428 is where its indigo and anything below that is just identical to 405nm
 
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RedCowboy

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These 5W Sharp 440nm laser diodes certainly look to be a shorter wavelength than the N1ch1a 445's, but I don't have a spectrometer to measure them.



 

CurtisOliver

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I would love to help you, but my laptop that i use for my spectrometer fell and no longer works until I can get it apart and see what damage was done to it. Sorry Curtis. :(
No worries Paul. Thanks however, I hope you get that fixed.

the one i tested was rather low but i'm not sure if mine was just defective. I picked up a cheap sanwu striker and it started out around 435nm and settled ~440nm doing the full 7.5w. this is the only nubm44-v2 i've had and tested so i'm not sure if this is standard. color looks identically to 445-450nm though so don't get your hopes up for a nice indigo color. everything from 430-450nm looks more or less identical to the human eye in my experience. 422-428 is where its indigo and anything below that is just identical to 405nm
That does seem like an oddball diode. Don’t think I’ve heard of one that low before. It isn’t so much the colour, I need <445nm for a project with a high power diode. Thanks

These 5W Sharp 440nm laser diodes certainly look to be a shorter wavelength than the N1ch1a 445's, but I don't have a spectrometer to measure them.



I totally forgot about those sharps. Thanks red. In hindsight I should of probably revisited jnrpops diode thread for more options.

5W+ at <445nm is required. I will be using a TEC to control the wavelength.
 

RA_pierce

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Why not check datasheets?
You may not be able to find one for the exact product you have in hand, but you can compare temperature and wavelength curves for similar diodes and make a pretty good estimation based on that information.
I've attached screenshots from a couple 450 nm laser diodes.

Also, why would you be interested in the current versus wavelength measurement? Current is going to be correlated with emission wavelength but my understanding is that temperature is the main driver of wavelength shift.
Individual measurements from people running them will not paint an accurate picture without many data points. Once you factor in calibration error for the various spectrometers being used and the different operating conditions for each user's diode, you end up with a noisy mess. It seems simpler to just use the datasheets. After all, the manufacturers of these laser diodes systematically test their products in quantity in controlled environments, so their data will be superior to sparse crowd-sourced reports.
 

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ZRaffleticket

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Why not check datasheets?
...
Also, why would you be interested in the current versus wavelength measurement? Current is going to be correlated with emission wavelength but my understanding is that temperature is the main driver of wavelength shift.
Potentially because we push these diodes well past their ratings, which wouldn't reasonably be expected to be provided in datasheets? Just my $.02. If staying within ratings then absolutely just refer to the datasheets. (I should proofread before posting, not after. Of course it's within ratings, we want to shift down. Whoops.)

Second point, temperature is less significant for GaN based diodes (at least compared to AlGaAs).


What are you trying to do Curtis? Just documenting, or are you actually trying to shift something down a ton yourself? If you're trying to shift a lot you may want to take a step further and tune with a diffraction grating as temp+current will only get you so far. If you're aiming for a high power <445nm, as mentioned Sharp has some options. I'll see if I can get my hands on either:
435nm - gh04c05w9g
440nm - gh04c05v9g
 

CurtisOliver

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Why not check datasheets?
You may not be able to find one for the exact product you have in hand, but you can compare temperature and wavelength curves for similar diodes and make a pretty good estimation based on that information.
I've attached screenshots from a couple 450 nm laser diodes.

Also, why would you be interested in the current versus wavelength measurement? Current is going to be correlated with emission wavelength but my understanding is that temperature is the main driver of wavelength shift.
Individual measurements from people running them will not paint an accurate picture without many data points. Once you factor in calibration error for the various spectrometers being used and the different operating conditions for each user's diode, you end up with a noisy mess. It seems simpler to just use the datasheets. After all, the manufacturers of these laser diodes systematically test their products in quantity in controlled environments, so their data will be superior to sparse crowd-sourced reports.
Well considering the same diode has had two different variations where the central wavelength was different I wouldn’t put any accuracy in comparing with another diode altogether. I get your premise, but not a reliable way of knowing it can hit that wavelength. Instead a binned diode seems to be the best way of making 100% sure I’ll get the wavelength needed. As we all know every individual diode behaves differently.

Potentially because we push these diodes well past their ratings, which wouldn't reasonably be expected to be provided in datasheets? Just my $.02. If staying within ratings then absolutely just refer to the datasheets. (I should proofread before posting, not after. Of course it's within ratings, we want to shift down. Whoops.)

Second point, temperature is less significant for GaN based diodes (at least compared to AlGaAs).


What are you trying to do Curtis? Just documenting, or are you actually trying to shift something down a ton yourself? If you're trying to shift a lot you may want to take a step further and tune with a diffraction grating as temp+current will only get you so far. If you're aiming for a high power <445nm, as mentioned Sharp has some options. I'll see if I can get my hands on either:
435nm - gh04c05w9g
440nm - gh04c05v9g
As the NUBM44 doesn’t actually have an official data sheet it will be ran at a sensible current setting. And then stabilised at 25 deg C by a TEC. InGaN seems to have a thermal shift of 0.7-1nm/C which is definitely low compared to red emitting semiconductors.

I need a specific wavelength and for it to be stable at high power. So I just need to know a) is the NUBM44 definitely capable of <445nm operation naturally. b) Does it need excessive cooling and current limiting to achieve it.

So after some of my own research I have found that the diode is capable, as some companies offer the option of buying diodes binned to the wavelength required and tell you the output power expected.

So this seems like the best option than taking a random diode and forcing it there.

Thanks for all responses, and hopefully in the near future you’ll see why this information was needed.
 




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