445nm Laser is bright at first then dims.

[supadots]

just out of curiosity, why does the diode dim as apposed to just completely dying when it is supplied such a high current. dont they usually just die?

 

[lazeerer]

Hey Guys,

I got the diode and driver in today to test and see what was up.

I made a video of it.

As you can see the driver is just fine .:beer:

Not a slightest Clue what this is except for a few guesses.

But what it appears to me and again this is just a guess, What it appears to be is either a couple of the bonding wires snapped and is not able to take the currant and is causing it to dime out.
OR
The Die itself has become dismounted from the heatsink mount it sits on to keep it cool and is overheating and due to this it has suffered damage and is why its not lighting up until it gets to ~1A of currant.

Thats the best i can think of for now without being able to look through the diode window.

But to think that could happen and the die has become dismounted is Extremely rare IMO. So i dont know what it could be other then my guess.


Ive Never Ever seen this before. With all the amount of diodes that has passed through me, never once have i seen a diode do this.:undecided:

SO this got to be a rare happening.

 

[grainde]

Hey Angelos mine did exactly the same thing, if you remember.

At the time I thought it might have been the bond wires disconnecting as the diode heated, but if that were to have happened at 1.8 A, the remaining bond wires would have had to carry the current...This is unlikely as they would just burn out and the diode would not come back to life.

Im really curious as to why this has happened. Are you able to de-can diodes and take a look?

Anyway, here's a vid of the raw output I took at the time for DTR.:beer:

 

[DTR]

I just saw the video and realized that diode has to be at least 6 months to a year old purchase from me as it has the old G-2 barrel and is in a brass module which neither I have carried in a long time.

Anyway yea that is crazy the only thing like it I have seen is the one grainde had which was a long time ago as well. His was an instant flash though it looks like this one hangs in there for a little longer but it could be just because it is being driven precisely at the lasing threshold. I am also at a loss to what could have caused such damage. Supadots I am guessing this diode was in storage for a very long time and just assembled? From what it looks like that driver is also one of the first batches of X-drives.

 

[supadots]

yeah i put the project on the shelve for a few months (bought it last summer?) after it didnt work. at the time we thought it was the batteries, and i had tried many different sets including the power supply. i just gave up after a couple weeks.

ive noticed the G2 lens is pretty loose inside the module, are there any materials i can wrap/paint/heatshrink around it to make it a tighter fit?

 

[Blord]

You can add a spring for some tension between the lens and module. Or wrap one layer of Teflon tape around the lensbarrel. That should eliminate the sloppiness.