Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

How to Register on LPF | LPF Donations

New 9mm 445 diodes

pullbangdead said:
Anybody remember my diode microscope pics? I'd like to compare A, M, and 9mm with enough mag to measure ridge width. Any volunteers?
Click to expand...

These are headed over to someone to take micro pics

If his suck, (or even if they're good) would you like these shipped to you next?

The purpose of the micros is to try to get a measurement of the ridge and the wires

Peace,
dave
 





daguin said:
These are headed over to someone to take micro pics

If his suck, (or even if they're good) would you like these shipped to you next?

The purpose of the micros is to try to get a measurement of the ridge and the wires

Peace,
dave
Click to expand...

Dave,

I will send them out Monday first class - is that ok? Or do you prefer some other shipping/tracking etc?
 
Interesting that this one actually has a datasheet of what is probably this diode on N's site. It makes the case all the more strong that the previous generation in the 5.6mm package were likely from the same manufacturer, which I think we all assumed anyways.

Here's a vote for PBD to take some fancy macros, although I have to say tsteele really cranked out some good ones :D

I think it would just be interesting to see the cavity length, if they made any obvious changes to the facet coatings, and just to see such a tiny work of technology :wave:
 
Wait I missed that...

Is there a known data sheet?

DTR, please post a link in the first post! :)
 
Its speculation that these are N. Diodes, The fact is nobody really knows for sure even if the diode is 90% visually identical and has the same features. They could be copies or even copy/enhancement manufactured by Joe blogs in china. They could even have the same G-code as N. diodes. In the end it does not matter who made them or if the data sheet is the right one or not. They are cheap, powerful and tough.
 
I'm just saying that while it is speculation, we are more confident than before that these are Nichia diodes. I think I worded it strangely...

JayRob, I just looked on Nichia's site and looked at the datasheet for the only high power 440-450nm diode they have, and it is such an oddball compared to all their other marketed offerings.
All of the other ones have a photodiode built into the package. This one does not.
All of the other ones do not have a static protection device. This one does.
Plus, the package size and description now fits.

I'd be flabbergasted if these were "knock-off" diodes. And also amazed that someone could pull off a copy.
 
BShanahan14rulz said:
I'm just saying that while it is speculation, we are more confident than before that these are Nichia diodes. I think I worded it strangely...

JayRob, I just looked on Nichia's site and looked at the datasheet for the only high power 440-450nm diode they have, and it is such an oddball compared to all their other marketed offerings.
All of the other ones have a photodiode built into the package. This one does not.
All of the other ones do not have a static protection device. This one does.
Plus, the package size and description now fits.

I'd be flabbergasted if these were "knock-off" diodes. And also amazed that someone could pull off a copy.
Click to expand...

I totally agree but in the end it does not matter.
 
We'll see how the next batch of images comes out, maybe my pictures would be worth the effort.

Hell, I'm curious enough about these that I might even stick them in the SEM too. The optical microscopes here will definitely show cavity length and ridge width, but there's another one or 2 things I'm curious about. I mostly want to see if the ridge width/length has changed, or if the bins are simply getting better (the "old" diodes were 1200um long and 15um wide, IIRC), but I'm curious of other things as well..

Also, with a look in the SEM I can tell you definitively if they're from Nichia or not. Not that it really matters though. Maybe I could tell with the microscope too, but it's tough to get the objective close enough for high-mag shots from above. Like in the last thread I posted images in, I could go much higher mag looking at the facet because the can isn't in the way, it's a very small working distance.
 
Last edited:
Ran some spectrometer tests on the diode I got from DTR.

Here's the nutshell:
500mA, 443nm
1000mA, 445nm
1500mA, 447nm
2000mA, 450nm

I won't comment on the actual wavelength, because that will probably vary from diode to diode even with these 9mm units. However, I'll note that the response to current increases is fairly typical for the diodes we're used to. When I search for really high wavelength diodes (the 457 and 458nm gems), I always bin based on performance at 1000mA. Generally, I expect to see a 5nm increase as current moves from 1A to 1.8A. In fact generally most of the wavelength gains come from that range between 1000mA and 1800mA. So, this diode is on par.

I want to provide one really big caution:

Please, let nobody take this data as an indication that "the 9mm diodes are 450nm". I can just envision such a statement incorrectly circulating as gospel. It would be an incorrect interpretation of these results. I'll facepalm you and slap you with a trout ;) Diodes from the same array consistently vary at least 10 nm between extremes. Since we started decoding diode serials, I've even had the ability to compare almost consecutive diode serials, and even they vary. So the data above is just ONE reading of ONE diode, and is no more authoritative than randomly spectrometering ONE diode from an M series projector. Really, the only value to the data above is in confirming two facts:

1) There's no reason to suspect that these 9mm diodes are all some new wavelength.
2) They tend to react to current increases identically to how 5.6mm diodes react.

attachment.php


attachment.php


attachment.php


attachment.php
 

Attachments

  • 500mA.png
    500mA.png
    17.8 KB · Views: 751
  • 1000mA.png
    1000mA.png
    17.7 KB · Views: 723
  • 1500mA.png
    1500mA.png
    18.5 KB · Views: 683
  • 2000mA.png
    2000mA.png
    18.6 KB · Views: 11,069
Wow, i didn't know current had that effect on wavelength,

What role does temperature play in that data?
If you hold current constant, and change temperature, how is wavelength effected?
 
justinjja said:
Wow, i didn't know current had that effect on wavelength,

What role does temperature play in that data?
If you hold current constant, and change temperature, how is wavelength effected?
Click to expand...

Temperature either:
1) Has almost no impact
or
2) Has the impact so instantaneously that you can't identify it's impact

If I cold-started the diode at any particular wavelength in that range, I would typically see it at most 2nm lower than the final "hot" wavelength. That's REALLY an "at most". Generally the shift as the duty cycle proceeds, if there is one, is like 0.5nm, maybe 1nm. Basically within one or two increments of the spectrometer's minimum resolution.

So keep in mind that the time from starting the laser, to moving my attention back to the spectro software and taking that first "cold" reading, is probably 5 seconds. The change between say 5 seconds in and 2 minutes in, is almost nothing. So either temperature really has no effect, OR the major brunt of that effect is felt within just a few seconds (possible if the emitter gets hot almost immediately).

Either way, the practical implication is that you wavelength won't typically shift while it's just sitting there.
 
rhd said:
I want to provide one really big caution:

Please, let nobody take this data as an indication that "the 9mm diodes are 450nm". I can just envision such a statement incorrectly circulating as gospel. It would be an incorrect interpretation of these results. I'll facepalm you and slap you with a trout ;) Diodes from the same array consistently vary at least 10 nm between extremes.
Click to expand...

Don't test him folks. He WILL do this. I have been face palmed by him several times and once I even thought that I saw a trout behind his back.
 
You must log in or register to reply here.


Back
Top