Re: V1 445nm Laser Diode
Here is some testing that i did the other night on the array long canned diodes NUBM05T / NUBM41T1. (The 3.6W version long/open can)
Thought i should put it up here so we can compare to the New Canned ones that come in the same array block that we are waiting to test now.
Here is what i noticed. I have tested so far only 3 of these diodes and they have been a little more random in both Wavelength and Power compared to the NDB7A75/NDB7K75 3.5W canned diode when it comes to falling within the same power and Wavelength group from one diode to another. The 3.6W Long Can ones are still greater in power then the 3.5W NDB7A75/NDB7K75 diodes by quit a bit depending on your diode "more info below" however the wavelength is lower on the 3.6W diodes so brightness will be effected even though they put out more power. What iam saying is it would be nice if these all fell in a nice power group where they all did +/-500mW from one another. All 3 of these diodes came from the same array block so we definitely need more testing on more diodes from several arrays to make sure this is not some fluke. But for now this is what i got.
As for the NDB7A75/NDB7K75 3.5W diodes ive tested 12 so far in a span of a few months and had a couple from when they first came out way back. I have not noticed a difference from then till now with improvement on these. The Improvement seems to be the 3.6W diode. Nothing in great detail with my testing on these but simply tested at 4A current at ~30C and a WL check that was it for me. All these diodes in short where consistent from one another in that the power at 4A ranged anywhere from 5W to 5.5W and the wavelength stayed between 451nm and 454nm. Cooling them also Improved the power by ~500mW at 0C.
Now the NUBM05T / NUBM41T1 3.6W array diodes with the long can these are the numbers iam getting. Since the new canned ones we are waiting to arrive are in the same array block this is what diode we should compare them too:
Diode 1: At 4A it did this:
I was Not able to test the full MAX power of this diode as i killed it hitting it with 12V bumping the supply pot.
But this one looked like it would have done near 8W if i pushed it right before the roll back like i did with diode 3 bellow.*retardo
Diode 2: At 4.1A it did:
MAX power is ~6.2W at 5A and then it roles back at around 5.1A.
Diode 3: At 4A it did this which is pretty close to exactly the same as the New Canned one DTR Just tested:
Just a Note: This diode is 445.6nm at right above threshold.
Where it gets interesting which DTR does not see on the canned diode he tested because of his meter limitations, diode 3 breaks 7W and rolled back at ~5.6A.
NOTE: This is not the canned diode that DTR tested. It is the 3.6W open can ones. Iam just mentioning and comparing to his numbers for that diode he posted numbers on showing that Diode 3 is similar in performance to the canned one he tested.
Video
(Turn speakers down I forgot to turn the music down in the work room)
In this video no temp regulation but the entire back of the diode was pressed flat to a solid copper back.
Please note ALL these diodes tested in this post is the NUBM05T / NUBM41T1 Long can/open can 3.6W diodes Not the New One DTR just found with a Can on it that he tested. Iam not saying they are the same but for now similar at the very least till i get my diode in to test and see how "Similar or the same and or different they are" I don't want to confuse anyone.:beer:
If you noticed and ive seen this plenty of times before in all the 5.6mm/9mm blues the More efficient the diode is the lower the laser diode Wavelength is. The Less Efficient the diode is the Higher the Wavelength is.
The Roll back on diode 3 was ~5.6A at the temperature i listed. Going passed that to 6A and it really started to roll back quick. The decrease started off slow but then picked up quick and started dropping 200mW of power every second just about. I let it go down to ~3W
to see what would happen and turned the current back down from 6A to 4A and it recovered like nothing ever happened. These guys are robust!>
So what iam thinking is heat plays a big factor in the role back and where it takes place. I have a feeling that the 9mm package these diodes come in is a limiting factor in the roll back so when having the diode cooled and regulated i think they will take more current or see an increase in power greatly. Every diode has a role back or death at some point but i think heat is causing this early if you allow the diode to heat up more and more. More testing is needed but cooling seems the way to go.
Another thing to notice during the role back and the power was drop to ~3W i looked at the spectrometer and noticed the WL had gone up to 460nm.
One of the diodes (Diode 3) when the diode was at 45C the roll back started earlier then when it was at 32C. At 45C the roll back started at ~4.8A and it did ~700mW less in MAX power.
These diodes will most definitely need to be mounted in a module where the entire back of the diode is sinked. Especially for running them at above the datasheet recommendation.
For the 3.6W NUBM05T / NUBM41T1 long can diodes the Power ranges ~1W to possible near 1.5W from diode to diode depending on the diode you get and for Wavelength about ~7nm to possible 10nm when you have the temp regulated and running the diode near its MAX. (Based on my 3 diodes.) These appear to be more 445nm in Wavelength rather then the 450nm/455nm diodes that the 3.5W NDB7A75/NDB7K75 are and that we are use to seeing today in the lower power 9mm/5.6mm diodes.
It looks like the more efficient diodes will be lower in WL of 450nm or less. Cooling them for sure. We might see 9-10W out of the efficient ones when super chilled.>
I plain on Cooling one down to ~-25C (its about the coldest i can get with TEC at the moment) either tonight or when the new canned version arrives and do it side by side and see what kind of power increase i can get as well as current increase over running these diode with just passive cooling. Max power is temperature dependent.
Now these new diodes that have the can on them i have one on the way to test also. But i wanted to put up these graphs and talk about the 3.6W diode so everyone else testing these new canned ones can see what the 3.6W long tube ones performed like. At least its a start to compare too and hopefully more info will arise about them too. I have not seen much testing on these yet and iam thinking that the New Canned diodes are the same but possible just an improved version that has a cap based on diode 3 and diode 1 performance.
The 3.6W and the 3.5W diodes have the same beam profile and probably so do these new canned ones. I think we might need to go to a short FL lens like the 2mm FL lens Dave has for the P73/Oclaro's with some C lenses because the 3.5W/3.6W diodes have larger divergence then the 2W 9mm diode. But that's yet to be explored by me. I don't have alot of C-lenses to play with.
One thing iam interested in is the sharpness between the Open can 3.6W diode,the 3.5W diode and the new canned one we are waiting on.
What iam hoping for is these new Canned ones are higher in WL and more consistent in power from one another in the high end.
We need more then a few diodes tested to confirm this and from several different array blocks. You can see from the above 3 i test of the 3.6W open can diodes the group is not all that tight in the output power. Wavelength can be excused since typically 5nm is normal from one diode to another if they are not binning diodes at manufacture..
Really looking forward to see Planters testing on this diode.
Ill post my finding too.:beer: It be great to see more tester post too with more info so we can build up some nice data on them.
This is exciting.:wave:
